a

GAO

United States General Accounting Office

Report to Congressional Requesters

September 2002 OREGON INLET 

JETTY PROJECT

Environmental and 

Economic Concerns 

Still Need to Be 

Resolved

GAO-02-803

Page i GAO-02-803 Oregon Inlet Jetty Project

Contents

Letter 1

Results in Brief 2

Background 6

Corps Generally Has Not Maintained the Oregon Inlet Ocean Bar 

Navigation Channel at Its Authorized Depth 14

Corps’ Economic Analysis for the Proposed Oregon Inlet Jetty 

Project Has Several Limitations That Undermine Its Usefulness 

18

Performance of Similar Jetty Projects Has Been Mixed 25

Corps Applied Lessons Learned from Similar Jetty Projects in 

Designing the Oregon Inlet Jetty Project, but Information on Fish 

Larvae Migration Is Not Available 31

Commerce and Interior Remain Concerned That the Oregon Inlet 

Jetty Project Will Harm the Environment 32

Conclusions 38

Recommendations for Executive Action 39

Agency Comments and Our Evaluation 39

Scope and Methodology 41

Appendixes

Appendix I: The Corps’ Process for Developing Water Resource 

Projects 45

Appendix II: Chronology of Significant Events for the Oregon Inlet Jetty 

Project, 1950 through 2002 46

Appendix III: Approved Oregon Inlet Dredging Operations That Were Not 

Performed 54

Appendix IV: Review of Corps’ Economic Analysis of the Proposed Oregon 

Inlet Jetty Project 55

Appendix V: Comparison of the Proposed Oregon Inlet Jetty Project to 

Similar Completed Jetty Projects 75

Appendix VI: Comments from the Department of the Army 76

Appendix VII: Comments from the Department of the Interior 78

Appendix VIII: Comments from the Department of Commerce 82

Appendix IX: GAO Contact and Staff Acknowledgments 87

GAO Contact 87

Staff Acknowledgments 87
Page ii GAO-02-803 Oregon Inlet Jetty Project

Tables Table 1: Estimated Average Number of Annual Trips Made by 

Commercial Fishing Vessels through Oregon Inlet, for the 

Periods 1984-1986 and 1999-2001 21

Table 2: Performance of the Eight Jetty Projects Incorporating 

Weirs 26

Table 3: Approved Oregon Inlet Dredging Operations That Were 

Not Performed for Some of the Fiscal Years from 1990 

through 2001 54

Table 4: Comparison of Estimated Annual Benefits and Costs of 

Alternatives for Achieving a 20-Foot-Deep Navigation 

Channel for Oregon Inlet 57

Table 5: Summary of Information in U.S. Coast Guard

Investigation Files on Vessel Losses at Oregon Inlet, 

1961 through 1986 63

Table 6: Listing of Vessel Losses and Deaths Attributed to 

Conditions at Oregon Inlet, June 28, 1986, through 

November 27, 2001 64

Table 7: Listing of Vessel Damages Attributed to Conditions 

at Oregon Inlet between June 28, 1986, and 

September 30, 2001 66

Table 8: Key Characteristics of the Proposed Oregon Inlet Jetty 

Project and Similar Completed Jetty Projects 75

Figures Figure 1: Oregon Inlet’s Location Along the North Carolina and 

Virginia Coastlines 7

Figure 2: Aerial View of Oregon Inlet on September 18, 2001 9

Figure 3: The Corps’ Proposed Design for the Oregon Inlet Jetty 

Project as of September 2001 13

Figure 4: Funding Requested, Approved, and Expended for 

Dredging the Oregon Inlet Ocean Bar Navigation Channel, 

Fiscal Years 1990 through 2001 15

Figure 5: The Weir in the North Jetty at Masonboro Inlet, North 

Carolina 28

Figure 6: The Dual Jetty Project at Colorado River Inlet, Texas 30
Page iii GAO-02-803 Oregon Inlet Jetty Project

Abbreviations

CEQ Council on Environmental Quality

DOI Department of the Interior

EIS Environmental Impact Statement

FWS Fish and Wildlife Service

GAO General Accounting Office

GDM General Design Memorandum

NMFS National Marine Fisheries Service

NOAA National Oceanographic and Atmospheric Administration

NPS National Park Service

OMB Office of Management and Budget
Page 1 GAO-02-803 Oregon Inlet Jetty Project

United States General Accounting Office

Washington, D.C. 20548

A

September 30, 2002 Letr

The Honorable Max Baucus

United States Senate

The Honorable John Edwards

United States Senate

Oregon Inlet is the primary route to the ocean for hundreds of commercial 

and recreational fishing vessels operating in the Outer Banks region of 

North Carolina. However, the inlet experiences more high winds, strong 

tides, and shifting sand than any other inlet on the Atlantic coast of the 

United States. This high-energy environment often creates sand bars and 

large breaking waves at the inlet’s entrance to the ocean, commonly known 

as the ocean bar. These conditions, especially when combined with the 

severe storms that frequent the area, can swamp a boat or run it aground, 

imperiling both life and property. According to the U.S. Army Corps of 

Engineers and U.S. Coast Guard data, over the 40-year period 1961 through 

2001, hazardous conditions in the inlet were a factor in 25 deaths and the 

loss of 22 vessels. 

In 1950, in an attempt to improve navigation at Oregon Inlet, the Congress 

authorized the Corps to dredge a channel in the inlet—called the ocean bar 

navigation channel—to a depth of 14 feet.1

 From 1960 through 2001, the 

Corps’ Wilmington District Office, which is responsible for maintaining the 

ocean bar navigation channel at Oregon Inlet, spent about $108 million 

dredging this channel.2

 Additional efforts to improve the safety of the 

channel are conducted by the U.S. Coast Guard, which is responsible for, 

among other things, maintaining the navigation aids that help guide vessels 

through the inlet. In 1970, in an effort to stabilize Oregon Inlet and in 

response to local concerns that a deeper channel was needed to 

accommodate fishing vessels and commercial traffic, the Congress 

authorized the construction of dual rock jetties and a 20-foot-deep ocean 

bar navigation channel for Oregon Inlet.3

 Since this authorization, the 

Corps has completed and updated numerous economic and environmental 

1

 P.L. 81-516, the River and Harbor Act of 1950, authorized the project, officially titled the 

Manteo (Shallowbag) Bay, North Carolina, project.

2

 All dollars in this report are 1997 dollars unless otherwise noted.

3

 P.L. 91-611, River and Harbor and Flood Control Acts of 1970.
Page 2 GAO-02-803 Oregon Inlet Jetty Project

analyses to determine if construction of the project is justified. In the latest 

update of its economic analysis, completed in 2001, the Corps estimated 

that the project would yield annualized net benefits of about $7.2 million 

over 50 years, largely from savings that were projected to be attained from 

reduced operating costs for commercial fishing vessels and increased 

activity by recreational boaters. Annualized costs were estimated at about 

$4.5 million. As a result, annual net benefits (benefits minus costs) for the 

proposed jetty project were estimated at $2.7 million. However, although 

the Corps and others have completed many studies over the last 30 years, 

the Congress has never appropriated funds specifically to construct the 

project. During this period there have been major disagreements among 

federal, state, and local governmental entities, including the Departments 

of Commerce and Interior, as well as among environmental, fishing, and 

recreational groups, about whether the project is economically justified 

and whether it would harm the environment by, among other things, 

increasing beach erosion and restricting the migration of fish larvae from 

the ocean to the sounds inside the inlet, where the larvae develop into fish.

You asked us to review several issues related to the Corps’ Oregon Inlet 

jetty project. Specifically, we agreed to (1) assess federal efforts to 

maintain the ocean bar navigation channel in Oregon Inlet, (2) assess the 

extent to which the Corps’ 2001 economic analysis of the jetty project is 

useful for decision making, (3) provide information on the performance of 

similar jetty projects, that is, those constructed with dual jetties and a low 

section called a weir,4

 (4) determine whether the Corps’ Wilmington 

District Office applied lessons learned from similar jetty projects in its 

design of the Oregon Inlet jetty project, and (5) identify and discuss 

concerns raised by the Departments of Commerce and Interior about 

development of the jetty project.

Results in Brief During the past 19 years, the Corps has had difficulty maintaining the ocean 

bar navigation channel at Oregon Inlet at its authorized 14-foot depth. 

Specifically, from 1983 through 1994, the Corps spent on average about $4.1 

million per year dredging the channel, but was only able to maintain the 

authorized 14-foot depth on average about 23 percent of the time. After 

1994, the Corps spent an average of about $2 million per year, but the 

4

 A weir is a section of a jetty that is lower than the rest of the structure. The weir is 

typically designed to allow water and sand to flow over it when the water level is greater 

than low tide.
Page 3 GAO-02-803 Oregon Inlet Jetty Project

percentage of time the channel depth was maintained at its authorized 

depth declined to about 15 percent. According to a 2001 engineering and 

design document issued by the Corps, its dredging efforts at Oregon Inlet 

have not provided a safe and navigable ocean bar navigation channel, and 

hazardous navigation conditions at the inlet will continue to cause the loss 

of human life and injuries as well as vessel losses and damages. 

Wilmington District Office officials said that the high-energy environment 

and storms associated with Oregon Inlet have often thwarted the Corps’ 

plans and depleted its funding for dredging the inlet. In addition, the 

district has sometimes had to reallocate funds that were earmarked for 

dredging Oregon Inlet to other district projects in response to emergencies 

caused by the frequency and magnitude of area storms. Further, because of 

the Corps’ limited dredging and the inlets high-energy environment, the 

Coast Guard has been unable to maintain and properly position its 

navigation buoys for the channel, which further increases the risk of 

damage to vessels and injuries to people.

The Corps’ most recent economic analysis of the proposed Oregon Inlet 

jetty project, issued in 2001, has several limitations, and as a result, does 

not provide a reliable basis for deciding whether to proceed with the 

project. For example, the Corps relied on outdated data to estimate the 

benefits to large commercial fishing vessels (trawlers). More recent data 

indicates that trawlers currently use the inlet far less than the Corps 

estimated in its economic analysis. On the other hand, the Corps did not 

analyze the potential benefits the proposed jetty project may provide to 

smaller commercial fishing vessels. However, because these smaller 

vessels have shallower drafts than trawlers, the extent to which they might 

benefit from the jetty project is uncertain. The analysis also did not 

account for the economic value of the lives that might be saved by the jetty 

project, which could understate benefits; it also overstated the cost of the 

current dredging program, and it used an overly optimistic assumption 

concerning future dredging needs that would tend to understate the cost of 

the jetty project. We did not assess the net effects of all the limitations we 

found with the economic analysis because obtaining the necessary data 

would require an inordinate amount of time and expense. These 

limitations, however, can result in either overstated or understated 

estimated benefits and costs. 

Of the eight completed jetty projects constructed similarly to the proposed 

Oregon Inlet jetty project, two are generally performing as planned. Of the 

six other similar projects, three have required more dredging and higher 

maintenance costs than expected, and two have had their weirs closed—
Page 4 GAO-02-803 Oregon Inlet Jetty Project

one because the responsible Corps’ District did not accurately determine 

the direction of sand movement and constructed the weir on the wrong 

jetty, and the other because of problems with the instability of the channel 

and with boaters using the weir as a shortcut, creating a safety hazard. 

According to the Corps, the problems at these five projects stemmed from 

inaccurate information on sand movement when the projects were initially 

designed. At the sixth project, more sand has accumulated in the 

navigation channel than expected, but this occurred because the Corps did 

not fully construct the area designed to collect sand deposits. As a result, 

according to the Corps, the navigation channel has been available at its 

authorized depth only about 20 percent of the time.

In designing the proposed Oregon Inlet jetty project, the Corps’ Wilmington 

District Office applied lessons learned from the construction of similar 

jetty projects and from internal Corps guidance. For example, the 

Wilmington District staff stated that from its construction and management 

of the Masonboro Inlet jetty project in North Carolina—one of two similar 

jetty projects that are generally performing as planned—it learned about 

the need for dual jetties, the proper length of a weir, and the effect of 

erosion on jetties. District staff stated that from internal Corps guidance 

they learned about, among other things, the importance of having accurate 

information on sand movement in designing the proposed Oregon Inlet 

jetty project. Nonetheless, the Corps stated that because each jetty project 

is designed for a unique environment, lessons learned from similar projects 

would not predict all aspects of the performance of the Oregon Inlet 

project. For example, the Corps incorporated a weir into the design of 

Oregon Inlet’s northern jetty to allow fish larvae that migrate near the 

ocean shoreline to travel over the jetty, through the inlet, and into the 

sound. None of the eight similar jetty projects with weirs were designed to 

provide for fish larvae migration. 

Both the Department of Commerce and the Department of the Interior 

support the goal of providing a safe navigation channel through Oregon 

Inlet for commercial and recreational fishing vessels. However, both 

departments support a dredging-only approach to achieve that goal in an 

environmentally acceptable manner. Commerce, which manages marine 

resources, including fisheries, and Interior, which manages the federally 

owned land upon which the jetties would be built, have raised several 

environmental concerns about the construction of the Oregon Inlet jetty 

project. For example, Commerce believes that constructing the project 

will cause unacceptable harm to commercial and recreational fishery 

resources by limiting the ability of fish larvae to reach habitat necessary for 
Page 5 GAO-02-803 Oregon Inlet Jetty Project

their development. Commerce is also concerned that the jetties will 

significantly alter sand movement in the vicinity of Oregon Inlet and 

damage beaches, dunes, beds of submerged aquatic vegetation, salt 

marshes, shallow water habitats, and other aquatic sites and resources. 

Interior believes that the jetties will increase beach erosion, especially on 

the south side of the inlet, and that the project’s sand bypassing system 

could harm coastline habitat and wildlife by depositing large quantities of 

sand onto Interior’s land each year without allowing sufficient time for 

recovery of the ecosystem. For these and other reasons, Interior has 

maintained that constructing the jetties is not consistent with the missions 

of its National Park Service (NPS), which manages the Cape Hatteras 

National Seashore to the north and south of Oregon Inlet, and Fish and 

Wildlife Service (FWS), which manages the Pea Island National Wildlife 

Refuge to the south of the inlet, and has denied the Corps the permits 

needed to build the jetties on Interior’s lands. To address the concerns of 

Commerce and Interior, the Corps revised its original jetty design to 

shorten the length of the jetties and incorporate a weir, which it believes 

will mitigate the concerns about fish larvae migration. The weir is also 

intended to facilitate the collection of sand, which the Corps plans to 

transport to adjacent beaches to address erosion. However, both 

Commerce and Interior have stated these actions will not achieve the 

desired results. In October 2001, because Commerce, Interior, and the 

Corps were unable to reach agreement on these issues, Commerce referred 

the matter to the Council on Environmental Quality—an entity established 

by the National Environmental Policy Act to resolve interagency 

disagreements concerning major federal actions that might cause negative 

environmental effects. Interior has also asked the council to consider its 

concerns. The Corps does not believe it should spend additional public 

resources to develop the project until it has assurances that the 

environmental issues will be favorably resolved. 

Lacking resolution of environmental concerns from the council and 

construction permits from Interior, we agree with the Corps that it should 

not pursue further development of the Oregon Inlet jetty project. If, 

however, both of these issues are favorably resolved, we are 

recommending that in order to have a reliable economic basis for deciding 

whether to proceed with the project, the Secretary of the Army direct the 

Corps to prepare a new and comprehensive economic analysis of the 

project’s costs and benefits that would provide the more current and 

complete information needed to justify construction of the project. In 

commenting on a draft of this report, the Departments of the Army, 

Commerce, and Interior generally agreed with our findings and 
Page 6 GAO-02-803 Oregon Inlet Jetty Project

recommendations. The Department of Transportation did not comment on 

our overall findings and recommendations, but offered specific technical 

comments.

Background The Corps’ mission is both military and civilian and involves providing 

quality, responsive engineering services to the nation. The Corps’ 

involvement in civil engineering projects, such as the proposed Oregon 

Inlet jetty project, comes under the auspices of the Director of Civil Works 

and falls into four broad categories: water infrastructure, environmental 

management and restoration, response to natural or man-made disasters, 

and engineering and technical services. The Corps is organized 

geographically into eight divisions and 41 districts that are responsible for 

implementing individual projects. The Corps’ Wilmington, North Carolina, 

District Office, part of the South Atlantic Division, is responsible for 

maintaining a safe and navigable waterway at Oregon Inlet. Appendix I 

provides a description of the Corps’ process for developing a water 

resource project. 

Oregon Inlet provides the only access to the Atlantic Ocean from inland 

waters located between Rudee Inlet in Virginia Beach, Virginia, about 85 

miles to the north of Oregon Inlet, and Hatteras Inlet in Hatteras, North 

Carolina, about 45 miles to the south. Oregon Inlet is located in the Outer 

Banks, a string of barrier islands along the coast of North Carolina. 

According to a study of Outer Banks sediment and inlet dynamics, these 

barrier islands and their migrating inlets consist of dynamic sedimentary 

deposits, which, left to nature, constantly move and change under the 

influence of waves, currents, and the change in sea level. Overall, these 

islands are slowly moving toward the mainland at an average rate of about 

4.5 feet per year. In addition, along the ocean side of the Outer Banks, the 

sands flow predominantly toward the south. For this reason, the islands 

and Oregon Inlet naturally move in a southerly direction. At least a dozen 

separate inlets have naturally opened and closed along the Outer Banks’ 

coastline over the three centuries that preceded the formation of Oregon 

Inlet.5

 Currently, there are three inlets along the Outer Banks: Oregon Inlet, 

Hatteras Inlet, and Ocracoke Inlet. Figure 1 shows the location of Oregon 

Inlet and its surrounding features.

5

 “The Outer Banks of North Carolina: Budget of Sediment and Inlet Dynamics Along a 

Migrating Barrier System” by Douglas L. Inman and Robert Dolan, Journal of Coastal 

Research, Spring 1989, Charlottesville, Virginia.
Page 7 GAO-02-803 Oregon Inlet Jetty Project

Figure 1: Oregon Inlet’s Location Along the North Carolina and Virginia Coastlines

Source: Corps’ Wilmington District Office.
Page 8 GAO-02-803 Oregon Inlet Jetty Project

Oregon Inlet experiences a combination of more high winds, strong tides, 

storms, and shifting sand than any other inlet along the Atlantic coast of the 

United States. These high-energy conditions often create hazards for 

vessels attempting to pass through the inlet to or from the ocean. Vessels 

making this passage use the ocean bar navigation channel, which extends 

from a point about 1,500 feet inside the Herbert C. Bonner Bridge 

(commonly known as the Bonner Bridge) to a point in the ocean called the 

ocean bar, about 10,000 feet outside the bridge.6

 At the ocean bar, sand 

naturally accumulates and waves break on the surface because of the 

shallow water. Nonetheless, hundreds of vessels pass through the inlet 

each year. In 1999 through 2001, according to North Carolina Division of 

Marine Fisheries data, on average, about 311 commercial fishing vessels 

used Oregon Inlet a total of about 3,900 times each year to access the 

ocean. During this period, commercial fishing vessels using the inlet 

landed more than 18 million pounds of fish at seafood dealers that operate 

inside the inlet.

The North Carolina Department of Transportation is currently evaluating 

preliminary plans for constructing a bridge that would replace the Bonner 

Bridge. The new bridge would be located farther west than the current 

bridge and may make landfall several miles farther south than the current 

bridge, possibly bypassing the Pea Island National Wildlife Refuge. 

According to a state engineer, the proposed elevated portion of the new 

bridge would be 5,000 feet long, which would allow the natural migration of 

Oregon Inlet to the south and also permit the navigation channel to be 

moved as conditions dictate. The proposed completion date for the new 

bridge is 2010. Figure 2 provides an aerial view of Oregon Inlet.

6

 The Herbert C. Bonner Bridge transverses Oregon Inlet and carries a highway that 

connects Bodie Island on the north side of the inlet to Pea Island on the south.
Page 9 GAO-02-803 Oregon Inlet Jetty Project

Figure 2: Aerial View of Oregon Inlet on September 18, 2001

Source: Adapted from a Corps’ Wilmington District Office photo mosaic.
Page 10 GAO-02-803 Oregon Inlet Jetty Project

The safety and navigability of Oregon Inlet has been the subject of a series 

of engineering, economic, and environmental studies by the Corps’ 

Wilmington District Office. In the 1960s, local officials and other interested 

parties told the Corps that the original 14-foot navigation channel 

authorized by the Congress in 1950 was not adequate because it was not 

deep enough to accommodate larger vessels and existing dredging was not 

sufficient to provide a stable channel at its authorized dimensions. 

Subsequently, the House and Senate Public Works Committees asked the 

Corps to study whether any modifications of the Oregon Inlet project were 

advisable. Based on this work, the Corps made recommendations that led 

the Congress to authorize the dual rock jetties and a 20-foot navigation 

channel for Oregon Inlet in 1970. The authorization increased the depth of 

the ocean bar navigation channel from 14 feet to 20 feet, in part to 

accommodate the use of larger, deep-draft commercial fishing vessels that 

were expected to use the inlet in the future.7

 

Between the 1970 authorization and September 30, 2001, the Corps’ 

Wilmington District Office has spent about $10 million (current dollars) 

designing the project and studying whether it was economically and 

environmentally sound before construction could begin. These studies 

have included at least four updates of the district’s economic analyses and 

four environmental impact statements, as well as various redesigns of the 

project. According to the Corps, it has also made a substantial effort to 

coordinate its efforts with other interested agencies. For example, the 

Corps stated that it has worked with the Department of Commerce’s 

National Marine Fisheries Service and the North Carolina Division of 

Marine Fisheries to develop data on fish catch and associated use of the 

inlet by commercial fishing vessels. The Corps also participated in a joint 

task force with the Department of the Interior in 1991 to determine the 

effect of the jetties and the project’s proposed sand bypass system on the 

adjacent shoreline. In response to concerns raised by the task force, the 

Corps revised the proposed project by, among other things, reducing the 

length of the jetties and incorporating a weir to facilitate sand bypass and 

fish larvae migration. On September 21, 2001, the Corps issued Supplement 

No. 2 General Design Memorandum (GDM) and Final Supplement III 

Environmental Impact Statement (EIS), which state that the dual jetties 

7

 Draft is the distance between the water level on a loaded vessel and its keel (bottom). The 

channel depth is determined by the loaded draft of a typical vessel as well as by factors 

including wave action and the extent to which the vessel “squats” in the water when it is 

underway due to propeller action. 
Page 11 GAO-02-803 Oregon Inlet Jetty Project

and the 20-foot navigation channel are economically justified and 

environmentally acceptable. The Corps document also found that current 

dredging efforts at Oregon Inlet have not provided a safe and navigable 

ocean bar navigation channel and concluded that hazardous navigation 

conditions at the inlet will continue to cause injuries and the loss of human 

life as well as vessel damages and losses. However, as of September 2002, 

the Congress had not appropriated funds to construct the jetty project.

Despite the many studies and modifications to the project that the Corps 

has made over the last 30 years, the Department of Commerce, the 

Department of the Interior, various environmental groups such as the 

Biodiversity Legal Foundation, and other interested parties such as the 

North Carolina Saltwater Fishing Club, do not believe their concerns have 

been adequately addressed by the Corps’ analysis, and they have continued 

to oppose the project. In general, these entities contend that the Corps’ 

economic analysis is unsound and that the jetty project will cause 

significant beach erosion and impede migration of fish larvae to habitat in 

the sound, potentially leading to a significant reduction in the overall fish 

supply. Further, these entities state that other factors, such as navigational 

errors, may contribute to the potential for loss of life at the inlet, a risk that 

would not be reduced by construction of the jetties. Commerce and 

Interior also anticipate that the project will have adverse impacts to 

designated Essential Fish Habitat in the immediate area of Oregon Inlet 

that is required by fish for spawning, breeding, feeding, or growing to 

maturity.8

 However, the jetty project is strongly supported by the state of 

North Carolina and the local commercial and recreational fishing industry, 

which contend that the project is needed to ensure safe passage for vessels 

through the inlet, particularly larger, deep-draft commercial fishing vessels.

Although the U.S. Coast Guard has not taken an official position on the 

project, it is directly involved in issues concerning Oregon Inlet. The Coast 

Guard is responsible for maintaining the buoys and markers used to guide 

vessels through the ocean bar navigation channel and other channels in the 

sounds on the inside of the inlet. Coast Guard units located in Hatteras, 

North Carolina, and Portsmouth, Virginia, maintain the navigation aids at 

Oregon Inlet. In addition, the Coast Guard Station Oregon Inlet is 

responsible for, among other things, search and rescue and boating safety 

8

 Identification of Essential Fish Habitat and requirements concerning its coordination and 

management are contained in the Magnuson-Stevens Fishery Conservation and 

Management Act, as amended by the Sustainable Fisheries Act of 1996 (P.L. 104-297).
Page 12 GAO-02-803 Oregon Inlet Jetty Project

in coastal waters and sounds from the Virginia-North Carolina border to 

approximately Hatteras Island, North Carolina. 

Figure 3 shows the Corps’ current design for the proposed jetty project. 

The project includes construction of dual rock jetties about 3,000 feet 

apart. The north jetty would be approximately 10,000 feet long; the south 

jetty would extend about 3,500 feet beyond the Pea Island terminal groin, 

for a total length of about 6,600 feet. The terminal groin is a rock structure 

that was completed in 1991 to protect the southern end of the Bonner 

Bridge by stabilizing and restoring the tip of Pea Island. At the time, the 

erosion of Pea Island was threatening the southern end of the Bonner 

Bridge. The project also incorporates a weir in the north jetty that is 

designed to serve two basic purposes: 1) to facilitate sand bypassing from a 

deposition basin to adjacent beaches and 2) to aid fish larvae migration 

from the ocean past the jetties, through the inlet, and into the sound. A 

detailed chronology of significant events related to the development of the 

Oregon Inlet jetty project is provided in appendix II.
Page 13 GAO-02-803 Oregon Inlet Jetty Project

Figure 3: The Corps’ Proposed Design for the Oregon Inlet Jetty Project as of 

September 2001 

Source: Adapted from Supplement No. 2 General Design Memorandum, Manteo (Shallowbag) Bay, 

North Carolina, Corps’ Wilmington District, September 2001. The map is based on May 26, 1996, 

aerial photography.
Page 14 GAO-02-803 Oregon Inlet Jetty Project

Corps Generally Has 

Not Maintained the 

Oregon Inlet Ocean Bar 

Navigation Channel at 

Its Authorized Depth 

The Corps has had difficulty maintaining Oregon Inlet’s ocean bar 

navigation channel at its authorized depth of 14 feet. According to officials 

in the Corps Wilmington District Office, from August 1983 through March 

1994 the 14-foot depth was maintained about 23 percent of the time.9

 

During this period, the Corps spent an average of about $4.1 million 

annually to dredge the channel. In recent years, however, expenditures on 

dredging the channel have declined to an average of about $2 million 

annually, and the Corps has been able to maintain the channel’s authorized 

14-foot depth only about 15 percent of the time. According to Wilmington 

District officials, the district has not been able to maintain the channel’s 

authorized depth because the inlets’ high-energy environment constantly 

moves sand back into the navigation channel and because funding 

limitations restrict the amount of dredging that can be performed. Officials 

said that the district does not get all of the funds it requests and often has 

to reallocate funds that are earmarked for dredging Oregon Inlet to respond 

to emergencies elsewhere in the district. The Corps’ limited dredging and 

the high-energy environment of the inlet also affect the Coast Guard’s 

ability to adequately maintain buoys that are supposed to mark the ocean 

bar navigation channel for vessels using Oregon Inlet. In fact, navigation 

charts for Oregon Inlet do not display the location of navigation aids, such 

as buoys, because they are frequently moved by the Coast Guard due to 

continuously shifting sand and by severe storms. These conditions 

increase the risk of danger to vessels and injuries to people.

The Inlet’s Environment and 

the Corps Limited 

Resources Have Hindered 

Dredging of the Ocean Bar 

Navigation Channel

Oregon Inlet experiences more high winds, strong tides, and shifting sand 

than any other inlet on the Atlantic coast of the United States. This highenergy environment is magnified by a high incidence of storms, particularly 

those from the northeast (called nor’easters) during the fall and winter 

months. For example, between 1990 and 1998, the Oregon Inlet area was 

affected by more than 100 significant storms, some of them hurricanes. 

Storms heighten ocean waves and increase sand movement in the inlet. 

Based on Corps studies, an average of about 2.1 million cubic yards of sand 

move in and around Oregon Inlet each year.10 In comparison, annual sand 

9

 The Corps calculates the percentage by periodically surveying the depth of the channel. If 

any portion is less than the authorized depth of 14 feet, the channel is considered 

unavailable.

10 The Corps’ estimate of sand movement is for the period 1956 through 1975 as presented in 

its September 2001 GDM on the jetty project.
Page 15 GAO-02-803 Oregon Inlet Jetty Project

movement for the two jettied inlets closest to the Oregon Inlet is about 

471,000 cubic yards for Rudee Inlet in Virginia and about 700,000 cubic 

yards for Masonboro Inlet in North Carolina. 

In addition to causing massive sand movement each year, district officials 

noted that the frequency and severity of storms at Oregon Inlet significantly 

affect the district’s budget and dredging plans. Specifically, according to 

district officials, their budget and dredging plans are prepared 18 to 24 

months in advance of the actual work. However, predicting storms that far 

into the future is impossible, and, for this reason, yearly budgets and 

dredging plans often differ significantly from actual needs. As a result, the 

district has often had to reallocate funds among its projects to meet 

immediate needs and is not able to perform all planned activities for 

Oregon Inlet, such as dredging. Figure 4 illustrates fluctuations in funding 

requested, approved, and expended to dredge the ocean bar navigation 

channel.

Figure 4: Funding Requested, Approved, and Expended for Dredging the Oregon Inlet Ocean Bar Navigation Channel, Fiscal 

Years 1990 through 2001

Note: Amounts are expressed in 1997 constant dollars.

Source: GAO analysis of data provided by the Corps of Engineers’ Wilmington District Office.
Page 16 GAO-02-803 Oregon Inlet Jetty Project

As shown in figure 4, in some years from 1990 through 2001, the district did 

not spend all of the funds that had been approved for dredging the ocean 

bar navigation channel; in other years, it spent more. For example, for 6 of 

the 12 years, the district received approval to spend about $22.5 million, but 

spent about $10.8 million, or about $11.7 million less than the approved 

amount. In those years the district reallocated the $11.7 million budgeted 

for dredging the Oregon Inlet ocean bar navigation channel to address 

other higher-priority emergency needs in the district. For example, in fiscal 

year 1999, reallocated funds were used to remove sand bars and debris that 

were causing hazardous navigation conditions in the Atlantic Intracoastal 

Waterway. These hazards had unexpectedly accumulated after a severe 

storm. Conversely, in the other 6 years, the district spent more funds than 

were initially approved for dredging the ocean bar navigation channel. 

Specifically, the district spent about $25.4 million, or about $6.5 million 

more than the $18.9 million that had been initially approved during those 

years. For example, in fiscal year 1991, the district received approval for 

about $4.7 million to dredge the channel, but spent about $7.0 million, 

which it obtained by reallocating funds from other projects within the 

district. District Office officials explained that in many of these years the 

district experienced several hurricanes and other storms that necessitated 

redirecting funds from some projects to perform emergency work on other 

projects.

Wilmington District Office officials said that another reason they often 

need to reallocate funds is because they do not receive all of the funding 

that they request. Although district officials noted that getting requested 

funding would not ensure that the ocean bar navigation channel was 

always maintained at the authorized depth of 14 feet, it would ensure that 

the authorized depth was maintained more often and would also reduce the 

amount of funds that the district has to reallocate among its projects during 

emergencies. For example, between fiscal years 1990 and 2001, the district 

requested about $55 million for dredging the ocean bar channel and 

obtained approval to spend about $41 million, or 75 percent of what it 

requested. 

For the most part, as shown in figure 4, the district has significantly 

reduced the amount of funds it has requested and spent on dredging the 

ocean bar navigation channel over the last few years. During this period 

there has also been a notable decline in the Corps’ ability to maintain the 

channel’s 14-foot depth. Specifically, between August 1983 and March 1994, 

when the Corps spent an average of about $4.1 million per year dredging 

the channel, it was able to maintain the authorized 14-foot depth about 23 
Page 17 GAO-02-803 Oregon Inlet Jetty Project

percent of the time. However, between March 1994 and October 2001, the 

Corps has only maintained the channel at its authorized depth about 15 

percent of the time. District officials explained that in the late 1980s and 

early 1990s, the district needed to dredge a large volume of sand that had 

accumulated in the navigation channel around the Bonner Bridge. Due to 

the location of this sand and the Corps’ desire to place it on Pea Island to 

prevent erosion, the district used a pipeline dredge to remove the sand. 

Generally, a pipeline dredge is significantly more expensive to operate than 

other types of dredges because of the cost to set up the pipeline that 

transports the removed sand to a new location. By the end of 1995, the 

Corps had successfully removed the sand affecting the navigation channel 

and deposited it on Pea Island. As a result, according to district officials, 

the district reduced its funding requests for 1996 through 2001 because it 

did not expect to use an expensive pipeline dredge to remove that much 

sand again during that period. However, during that time, there was a 

reduction in the Corps’ ability to maintain the ocean bar navigation channel 

at its authorized depth. 

District officials also said that their budget requests have never included 

the total amount of funds needed to maintain the ocean bar navigation 

channel at its authorized depth 100 percent of the time. District officials 

stated that in the past they could not justify spending the time and money 

needed to prepare a request for such an amount because there was little 

likelihood that the amount would be received. However, district officials 

stated that in their fiscal year 2003 budget request they included a request 

for $10.9 million, which is an amount they believe is needed to maintain the 

channel at 14 feet 100 percent of the time.

Oregon Inlet’s High-Energy 

Environment and the Corps’ 

Limited Dredging Have Also 

Reduced the Coast Guard’s 

Ability to Properly Mark the 

Ocean Bar Navigation 

Channel

The Coast Guard is responsible for maintaining the buoys that mark the 

Oregon Inlet channel. Coast Guard officials said that they have difficulty 

maintaining the buoys marking the location of deep water in the ocean bar 

navigation channel because the high-energy conditions in the inlet cause 

large amounts of sand to move in and out of the channel. This sand 

movement often changes the location of deep water and, when combined 

with the Corps’ limited dredging, results in sand accumulation around the 

buoys. According to the Coast Guard, when sand accumulates on the 

channel side of the buoys to a depth that approaches the draft of a buoy 

tender, it becomes difficult and sometimes impossible to relocate the buoys 

to mark deeper water. For example, on October 30, 2001, the Coast Guard 

asked the Corps to provide a vessel to relocate 6 of the 13 buoys that were 
Page 18 GAO-02-803 Oregon Inlet Jetty Project

located in the inlet at that time. The Corps vessel could operate in 

shallower water and had the lift capability to relocate the buoys.

In addition, as part of an ongoing waterway analysis and management 

program, the Fifth Coast Guard District reported on November 14, 2001, 

that the buoys in Oregon Inlet are always moving due to storms. The report 

states that after every large storm, several buoys at Oregon Inlet are either 

damaged, moved, or both, and it is difficult to maintain and keep these 

buoys in the proper location because of limited Coast Guard resources. 

According to the commanding officer of one of the Coast Guard vessels 

that services Oregon Inlet, there is no easy way to provide a reliable 

navigational aid system in Oregon Inlet. The commanding officer said that 

over the years buoys have been added and removed in attempts to properly 

mark the navigation channel, but the location of deep water changes 

regularly. The commanding officer also said that the north side of the 

channel is almost impossible to mark reliably because sand regularly shifts 

into and out of the channel as Bodie Island moves south, creating a 

constant navigational hazard.

The buoys that mark the deep water of the ocean bar navigation channel 

are frequently moved and are therefore not charted. According to Coast 

Guard officials, vessel operators who are not aware of the shifting sand 

conditions are susceptible to running their vessels aground. As a result, the 

Coast Guard suggests that vessel operators call its Coast Guard Station 

Oregon Inlet to obtain the most recent navigation data before attempting to 

traverse the ocean bar navigation channel.

Corps’ Economic 

Analysis for the 

Proposed Oregon Inlet 

Jetty Project Has 

Several Limitations 

That Undermine Its 

Usefulness 

We identified several limitations in the Corps’ economic analysis that 

undermine its usefulness for assessing whether the Corps’ preferred 

alternative of a dual jetty project with a 20-foot navigation channel is 

economically justified. For example, the analysis overstated the benefits to 

large commercial fishing vessels (trawlers) based on their current fishing 

activities, but did not analyze the potential benefits the proposed jetty 

project may provide to smaller commercial fishing vessels. However, 

because these smaller vessels have shallower drafts than trawlers, the 

extent to which they might benefit from the jetty project is uncertain. The 

analysis also did not account for the economic value of the lives that might 

be saved by the jetty project, which could result in understated benefits; it 

also overstated the cost of the current dredging program and used an 

overly optimistic assumption concerning future dredging needs that would 

tend to understate the cost of the jetty project. (See app. IV for more 
Page 19 GAO-02-803 Oregon Inlet Jetty Project

details on these and other limitations to the economic analysis.) We did not 

assess the effects of all these limitations on the net benefits of the Corps’ 

economic analysis because obtaining the necessary data would require an 

inordinate amount of time and expense. As a result, we cannot say what 

the net effect of addressing all the limitations would be on the net benefits 

and the benefit-cost ratio of the Corps’ preferred jetty project alternative.

Corps Estimate of Benefits 

to Commercial Fishing 

Vessels Is Based on 

Outdated and Incomplete 

Data

The Corps estimated that the recommended jetty project would generate 

about $2 million in annualized benefits by reducing the operating costs of 

commercial fishing vessels. The Corps anticipates that the recommended 

project would reduce these costs by alleviating hazardous conditions in 

Oregon Inlet that sometimes force the vessels, especially trawlers, to 

detour to more distant inlets or ports. The Corps based its benefit estimate 

on the savings that would occur if the number of detoured trips and their 

related operating costs were reduced. In estimating operating cost savings, 

the Corps included savings in “fixed” operating costs, which it defined as 

including, among other things, depreciation charges on the vessel, 

insurance, interest on loans, and taxes.

In calculating the estimated benefit, the Corps relied on data provided in a 

1987 consultant’s report that studied the number of trips taken by trawlers 

during the mid-1980s.11 However, these data do not reflect the fewer trips 

taken by trawlers in recent years. Further, the Corps overstated the 

operating costs savings that trawlers would likely achieve by including all 

the fixed-costs portions of their hourly operating costs. The appropriate 

measure of savings is variable costs (costs that vary with the length of 

fishing trips) that would be saved by reducing the number of detoured 

trips. This would include the cost of such items as fuel and oil but not such 

items as taxes and insurance, which likely would remain the same whether 

or not the jetty project is built.

In addition, by relying on the consultant’s study, the Corps excluded from 

its analysis the trips taken by smaller (shorter than 55 feet) commercial 

fishing vessels. These vessels were excluded because the consultant’s 

study did not assess the effect of inlet conditions on the operating costs of 

smaller fishing vessels. 

11 A Reassessment of the Economic Feasibility of the Oregon Inlet Project, 

Kearney/Centaur, a Division of A.T. Kearney, Inc., prepared for the Corps of Engineers, July 

1987.
Page 20 GAO-02-803 Oregon Inlet Jetty Project

As shown in table 1, according to data from the North Carolina Division of 

Marine Fisheries, about 97 trawlers averaged 679 trips through Oregon 

Inlet from 1999 through 2001.12 By contrast, the consultant’s 1987 study 

found that about 234 trawlers averaged about 4,500 trips through Oregon 

Inlet from 1984 through 1986. Both the state’s data and the 1987 

consultant’s study suggest that the number of smaller commercial fishing 

vessels using the inlet has significantly increased since the mid-1980s. 

State officials indicated, however, that because the state and the consultant 

used different methods to collect the data—the state’s data are based on a 

census of commercial fish landings and the consultant’s data were based 

primarily on interviews of selected seafood dealers and trawler captains—

the state’s data and the consultant’s data may not be fully comparable.13 We 

attempted to verify the data used by the consultant, but the Corps no longer 

has the supporting documentation for the study. Nonetheless, any 

assessment of the effect of the proposed jetty project on commercial 

fishing activities should be based on current commercial fishing trip data, 

which the state has collected through its trip ticket program. As a result, 

the Corps’ reliance on the consultant’s 1987 study calls into question the 

usefulness of the Corps’ estimate of the benefits of the jetty project to 

commercial fishing vessels. 

12 Data for 1999 through 2001 include landings made by both in-state and out-of-state vessels 

to seafood dealers in Dare, Hyde, Pamlico, and Beaufort Counties. According to state 

officials, trawlers using specified gear that land ocean-caught fish in these counties are 

assumed to pass through Oregon Inlet. Trips made by North Carolina vessels to land fish in 

other states are not included. Data for smaller vessels exclude fish that were landed in 

Hatteras (Dare County) because these landings are assumed to have been made using 

Hatteras Inlet

13 Under the North Carolina trip ticket program, which was begun in 1994, seafood dealers 

are required to report certain information about commercial fish landings, including the 

landing vessel’s identification, the species of fish caught, and the type of fishing gear used.
Page 21 GAO-02-803 Oregon Inlet Jetty Project

Table 1: Estimated Average Number of Annual Trips Made by Commercial Fishing Vessels through Oregon Inlet, for the Periods 

1984-1986 and 1999-2001 

a Vessels that are at least 55 feet long 

b Vessels that are shorter than 55 feet

c Source: 1987 Kearney/Centaur study

d Not available

e Source: North Carolina Division of Marine Fisheries. 

According to an official with the North Carolina Division of Marine 

Fisheries, the change in trawler trips likely reflects changes in federal and 

state limits on the fish harvest. For example, in 1992, several management 

measures---including a moratorium on the issuance of new licenses for 

fishing and a 13-inch limit on the size of fish that can be harvested---were 

implemented to reduce over-fishing of flounder, a fish species traditionally 

caught by trawlers operating out of Oregon Inlet. During the mid-1980s, 

before these resource management measures were imposed, about 7.7 

million pounds of flounder were landed annually through Oregon Inlet. By 

contrast, from 1999 through 2001, about 2.2 million pounds were landed 

annually through Oregon Inlet. According to Commerce, the size of the 

commercial fleet has declined due to a vessel reduction program 

implemented by the South Atlantic Fishery Management Council.

Corps officials said that they relied on the methodology of the consultant’s 

1987 report because they considered it “independent,” and that even 

though the trips by smaller vessels were not explicitly included in the 

analysis, the difficulties experienced by the trawlers were indicative of all 

commercial fishing vessels. In addition, the officials said that the recent 

trawler trip activity reflects, at least in part, a decrease in the reliability of 

the channel due to the lack of adequate operation and maintenance funds. 

They also said that the deeper channel provided by the proposed jetty 

project might attract other trawler operators to relocate to the Oregon Inlet 

area. However, the Corps’ assumption about the total hours delayed by 

inlet conditions is based on trawler trips, and it is not appropriate to apply 

the potential savings to smaller vessels without corroborating evidence 

Trawlersa Smaller vesselsb

Time period Number

Annual

trips

Number of

trips

detoured

Landings

(million lbs) Number

Annual

trips

Number of

trips

detoured

Landings

(million lbs)

1994-1986c 234 4,498 1,896 15 25 - 30 d d 2.8

1999-2001e 97 679 d 8.6 214 3,249 d 9.8
Page 22 GAO-02-803 Oregon Inlet Jetty Project

that they, too, are affected in the same way as trawlers. In addition, while 

the decrease in trawler traffic may reflect a number of factors, including 

fishery management measures and a decrease in the reliability of the 14-

foot channel, the Corps’ analysis is not useful for assessing these factors 

because it relies on data from the mid-1980s that do not reflect current 

commercial fishing vessel traffic, the fisheries management measures that 

have been put in place since the mid-1980s, or changes in the reliability of 

the channel. 

To illustrate how using the more recent trawler trip data would affect the 

Corps commercial benefits estimate, we adjusted the Corps’ analysis to 

account for the number of fishing trips that trawlers have recently taken. 

We also adjusted the Corps analysis to exclude certain fixed vessel costs. 

Based on these adjustments, we found that the annualized commercial 

fishing benefits would be reduced by about 90 percent, from about $2 

million to $194,000. However, accounting for the effect of the proposed 

jetty project on smaller fishing vessels could increase this adjusted 

estimate of the benefits to commercial fishing vessels. Because these 

smaller vessels have a shallower draft than trawlers, they may not be as 

affected by the sand accumulations in the ocean bar navigation channel 

that can be hazardous to trawlers. For this reason, the extent to which 

smaller vessels might benefit from the jetty project is uncertain. We could 

not assess the effect of the proposed jetty project on the smaller 

commercial fishing vessels because there are insufficient data on the 

extent to which these vessels are delayed by conditions in the inlet.

Corps’ Estimate of Benefits 

Did Not Incorporate the 

Economic Value of 

Accidental Deaths That 

Might be Prevented by the 

Proposed Jetty Project

The Corps did not incorporate the economic value of the lives that might be 

saved by the jetty project into its net benefit estimates. Consequently, to 

the extent that the jetty project reduces accidental deaths, accounting for 

the economic value of the lives saved could increase the benefits estimate 

(all other factors being the same). Federal guidance on water project 

analysis does not require that the economic value of the lives that might be 

saved by a project be included in the estimate of net benefits. Nonetheless, 

it is standard economic practice to incorporate this economic value into 

the benefits estimate so that decision makers can assess the full range of 

benefits that might be generated by a federal investment or regulation. For 

example, in assessing the benefits of safety improvements that reduce the 

risk of premature death, the Department of Transportation uses an 
Page 23 GAO-02-803 Oregon Inlet Jetty Project

estimate of the “value of a statistical life,” which is $3 million per averted 

death (2002 dollars).14

Corps officials said that their policy is to quantify the number of lives that 

might be saved by a project but not to estimate their economic value, 

because procedures for estimating the economic value of a life are not 

included in federal guidelines for analyzing water projects, and the Corps 

prefers that the project be assessed without the influence of the economic 

benefits attributable to lives saved. The officials said that they do consider 

the potential life-saving issues along with other factors, such as the benefitcost ratio, in deciding whether to recommend that a project be 

implemented. Nonetheless, an alternative approach that does not require 

valuation but explicitly considers lives saved can be useful for assessing 

whether projects that have negative net benefits (that is, “net costs” when 

costs exceed benefits or the benefit-cost ratio is less than 1) may still be 

worth implementing. Under this approach, the net costs (exclusive of lives 

saved) are divided by the number of lives saved, and the estimate can be 

compared with other federal investments to ascertain whether the 

proposed project’s estimate of net cost per life saved is comparable to that 

achieved by other federal investments or regulations.

The Corps estimated 14 accidental deaths would be prevented by the 

project. However, the Corps’ analysis assumes that all prior vessel 

accidents that included deaths would be prevented by the jetty project and 

does not clearly control for factors that would be present with or without 

the jetty project. For example, Corps officials told us that under some 

weather conditions the inlet would be hazardous even with the 

recommended 20-foot channel and dual jetties in place. Further, the Corps 

did not control for factors that include changes in type of vessel traffic, 

operator experience, and vessel safety technology, all of which will 

continue to play a role in the number of accidents and deaths in the inlet 

with or without the jetty project. In commenting on a draft of this report, 

the Departments of Commerce and Interior noted that the economic costs 

of the potential effect of the jetties on accidental deaths, vessel damage, 

and personal injuries resulting from the construction of the jetties are not 

incorporated in the analysis.

14 The value of a statistical life is derived from studies of individuals’ willingness to pay for 

small reductions in the risk of dying. The estimate represents the value of the reduction in 

risk to a population and not the value of any identifiable individual. 
Page 24 GAO-02-803 Oregon Inlet Jetty Project

Corps’ Estimate of Project 

Cost Does Not Include More 

Recent Data on Lower 

Expenditures and Uses an 

Overly Optimistic 

Assumption on Future 

Dredging Needs 

Using costs for dredging that the Wilmington District incurred from fiscal 

years 1983 through 1996, the Corps’ economic analysis estimated that the 

annualized cost of the current 14-foot dredging program is about $8.4 

million. The $8.4 million includes $6.5 million in average annual operation 

and maintenance (O&M) expenditures and about $1.9 million in other 

costs.15 In contrast, the Corps estimated that the proposed jetty project 

would cost $12.9 million ($6.1 million in O&M costs and $6.8 million in 

other costs).16 To determine the incremental or “net cost” that would be 

associated with implementing the jetty project alternative, the Corps 

appropriately subtracted the annualized cost of the current dredging 

program ($8.4 million) from the annualized cost of the proposed jetty 

project ($12.9 million). Based on this analysis, the Corps determined that 

implementing the jetty project alternative would cost $4.5 million more 

annually than the Corps spends on the current dredging program.

The Corps’ $6.5 million O&M cost estimate for the current dredging 

program is based on expenditures from fiscal years 1983 through 1996. 

However, for fiscal years 1997 through 2001, the Corps spent only about 

$3.9 million per year on dredging. By updating the Corps’ expenditure data 

through fiscal year 2001, we found that the Corps’ annualized estimate of 

the current dredging program would be reduced from $8.4 million to $7.4 

million.17 Consequently, the net costs of the jetty project would increase 

from $4.5 to about $5.5 million. Corps officials agreed that dredging 

expenditures have declined to about $3.9 million annually in recent years 

for the reasons cited earlier in this report.

In addition, in estimating the cost of the jetty project, the Corps excluded 

$945,000 that it spent from 1983 through 2001 dredging in Pamlico Sound, 

which is not part of the ocean bar navigation channel. The Corps excluded 

this cost because it assumed that dredging this area in Pamlico Sound 

15 The $1.9 million represents the annualized amount, at 7.125 percent interest, of dredging 

costs during the 4-year period required to construct the jetty project. 

16 The $6.8 million is the annualized value of the jetty project’s construction costs. 

17 The Corps made some computational errors in calculating the O&M costs for the current 

dredging program. Specifically, the Corps excluded $799,285 in costs that it had incurred 

dredging the ocean bar navigation channel in 1990, which it had inadvertently identified as 

an interior channel dredging expense. In addition, the Corps mistakenly double-counted 

$876,472 of costs incurred in 1991 to dredge the ocean bar navigation channel. We corrected 

for these two errors that essentially offset each other. Corps officials agreed with this 

correction.
Page 25 GAO-02-803 Oregon Inlet Jetty Project

would not be required as part of the recommended jetty project. Corps 

officials said that the source of the sand in this area is the ocean and, based 

on their best engineering judgment, this area will naturally flush itself after 

the jetties are built; therefore, this dredging cost will no longer be incurred. 

However, several coastal engineers and geologists familiar with the Corps’ 

proposed jetty project told us that the jetties would not eliminate dredging 

this area of the sound. In general, they believe that whether the source of 

the sand is the ocean or rivers that drain into the sound, the man-made 

channel will fill back in with the sand adjacent to it and require dredging. 

As a result, there is uncertainty about whether the Corps will continue to 

dredge this area. Nonetheless, if the Corps does have to dredge this area, 

then the cost of the jetty project would be higher than the Corps estimated 

in its economic analysis (all other factors being the same).

Performance of Similar 

Jetty Projects Has 

Been Mixed 

Corps district officials identified eight jetty projects located on the Atlantic 

Ocean and Gulf of Mexico coastlines that are similar to the proposed 

Oregon Inlet project in that they incorporate dual jetties and a weir. 

According to data provided by the Corps, two of these jetty projects, both 

south of Oregon Inlet on the Atlantic coast, are generally performing as 

planned, and six others are not. Two projects are considered by the Corps 

to be performing as planned because the Corps has not had to dredge the 

project’s navigation channel more than originally predicted. For the six 

jetty projects that are not performing as planned, one has a navigation 

channel that is frequently not at its authorized depth, three have required 

more dredging and higher dredging costs than expected,18 and two have 

had their weirs closed. According to Corps officials responsible for these 

six jetties, a key factor in why these jetties have not performed as planned 

was inaccurate information on sand movement when the projects were 

initially designed. According to the Corps and other experts, good 

estimates of sand movement are essential to successfully designing a weir 

jetty project that will facilitate the bypass of sand to adjacent beaches 

while ensuring the availability of a navigation channel with minimum 

dredging costs. Table 2 summarizes the performance of the eight dual jetty 

projects that incorporate weirs. 

18 Even with the additional dredging, for one of the three projects the channel has been 

available less than the expected amount of time. 
Page 26 GAO-02-803 Oregon Inlet Jetty Project

Table 2: Performance of the Eight Jetty Projects Incorporating Weirs

Source: GAO analysis of Corps data.

Two Projects Are Currently 

Performing As Planned

According to the Corps’ Charleston District staff, which is responsible for 

the Murrells Inlet jetty project, the project has performed as expected 

because maintenance dredging of the navigation channel, which was 

planned for every 3 years, has only been needed once since the jetty project 

was built. That dredging occurred in 1988, and additional dredging is 

planned for 2002. District staff said the channel through the inlet has been 

kept open primarily by the flushing action of currents flowing through the 

jetties and has had lower maintenance costs than expected.

The Corps’ Wilmington District staff, which is responsible for the jetty 

project at the Masonboro Inlet, said the project is considered to be 

performing as planned currently because they have only had to dredge the 

project’s sand deposition basin every 3 or 4 years, which is less than the 

planned frequency of once a year. However, the Masonboro Inlet project 

was originally constructed in 1966 as a single jetty with a weir on the north 

side of the inlet, which did not perform effectively. The 1,000-foot weir was 

the first structure of its type to be constructed in the United States. Tides 

and current undermined the jetty because the inlet’s channel continued to 

migrate. As a result, the Corps repaired the first jetty and, in 1980, 

Jetty project Location

More dredging than 

planned Weir closed

Poor channel 

availability 

Generally 

performing as 

planned

Murrells Inlet, SC Atlantic Ocean 

Coast X

Colorado River, TX Gulf of Mexico 

Coast X X

Ponce DeLeon, FL Atlantic Ocean 

Coast X

St. Lucie, FL Atlantic Ocean 

Coast X

Perdido Pass, AL Gulf of Mexico 

Coast X

East Pass, FL Gulf of Mexico 

Coast X

Rudee, VA Atlantic Ocean 

Coast X

Masonboro, NC Atlantic Ocean 

Coast X
Page 27 GAO-02-803 Oregon Inlet Jetty Project

constructed a second jetty on the south side of the inlet, which stabilized 

the locations of the channel and the sand deposition basin. After the south 

jetty was built, however, sand that the Corps predicted would accumulate 

in the deposition basin instead began accumulating at the south end of 

Wrightsville Beach. This sand eventually formed a spit and required vessels 

entering the inlet to make a sharp turn in strong crosscurrents in order to 

stay in the navigation channel.19 However, by using the sand spit as an 

extended deposition area, the Wilmington District has only had to dredge 

the deposition area every 3 or 4 years. According to district officials, this is 

also enough dredging to keep the spit from further encroaching into the 

navigation channel, which is otherwise kept open by the currents and tides 

passing between the jetties. (See fig. 5 for photographs of the Masonboro 

Inlet weir.)

19 A spit is a narrow point of land or sand mass extending from the shore.
Page 28 GAO-02-803 Oregon Inlet Jetty Project

Figure 5: The Weir in the North Jetty at Masonboro Inlet, North Carolina

The picture on the left shows that high tide covers the weir, while the picture at the right shows that the 

weir is exposed at low tide. The weir’s elevation is 2.16 feet above mean low water measured at the 

inlet.

Source: GAO.

Six Projects Are Not Performing 

As Planned

Project managers provided the following specific details about four jetty 

projects, including the jetty project that has incurred expected dredging 

costs, but whose navigation channel is frequently not maintained at its 
Page 29 GAO-02-803 Oregon Inlet Jetty Project

authorized depth, and the performance of the three jetty projects that have 

incurred higher than expected dredging costs.

• At St. Lucie Inlet, Florida, the Jacksonville District was performing the 

amount of dredging expected, but more sand accumulated in the 

navigation channel than was anticipated because the Corps did not 

complete construction of the deposition basin that was to collect the 

sand that passes over the weir. As a result, since the jetty project was 

constructed, the Corps has been able to maintain the navigation channel 

at its authorized depth of 16 feet only about 20 percent of the time. 

Plans are under way to complete construction of the deposition basin. 

The Jacksonville District believes that construction of the deposition 

basin, as well as other modifications to the jetty project, will help 

maintain the channel at its authorized depth 100 percent of the time.

• For the jetty project at Rudee Inlet built by the City of Virginia Beach, 

Virginia, officials said they expected to dredge 100,000 cubic yards of 

material annually. However, according to the city staff, actual dredging 

at the inlet has averaged 300,000 cubic yards annually because more 

sand than expected has flowed over the weir. Although the project has 

required more dredging than planned, a consultant for the city of 

Virginia Beach states that even with higher dredging costs, the 

expenditures are justified, because the inlet provides many recreational 

and commercial benefits.

• For the jetty project at Perdido Pass (inlet) in Alabama, the Corps’ 

Mobile District said that this project was designed for the Corps to 

dredge about 100,000 cubic yards of material annually; however, to keep 

the navigation channel at its authorized depth, the Corps has actually 

had to dredge about 361,000 cubic yards of material every 2 to 3 years.

• For the jetty project at the Colorado River Inlet in Texas, the Corps’ 

Galveston District expected to dredge about 536,000 cubic yards of sand 

every 2 years, or an average of 268,000 cubic yards annually. However, 

the actual amount of material dredged annually was about 680,000 cubic 

yards, or about two and a half times what was planned. The need for 

this additional dredging occurred because the amount of sand flowing 

over the weir has been greater than expected, and the sand has tended 

to be deposited in the navigation channel rather than in the project’s 

deposition basin. (See fig. 5 below for a photo of this project.) Despite 

the extra dredging, the Corps’ Galveston District reported that the 

channel was available at its authorized depth only about 30 percent of 
Page 30 GAO-02-803 Oregon Inlet Jetty Project

the time. The need for more dredging than planned has caused the 

responsible Corps districts to incur additional maintenance costs. For 

example, the Galveston District has spent about $1.9 million annually 

for dredging the Colorado Inlet, more than four times the $425,000 that it 

planned to spend for annual dredging when the project was designed.

Figure 6: The Dual Jetty Project at Colorado River Inlet, Texas

The east jetty is on the right and contains the weir, which is paralleled by a fishing 

walkway. More sand than expected has passed over the weir and been deposited 

in the channel, as indicated by the narrowing of the river in this view.

Source: The Corps of Engineers’ Galveston District.
Page 31 GAO-02-803 Oregon Inlet Jetty Project

The Corps districts had to close the weirs for two of the jetty projects 

because they did not work as planned. Specifically, in 1985, at the East 

Pass, Florida, jetty project, the Mobile District decided to fill in the weir 

that was built in 1969 because the east side of the weir was eroding, and 

only a limited amount of sand was accumulating in the deposition basin. 

The problem arose because the predominant direction of the sand flow was 

opposite to what the Corps expected when the jetty project was designed. 

In 1985, after the Corps determined that the weir was constructed on the 

wrong jetty, it closed the weir. In another case, in 1984, the Corps’ 

Jacksonville District closed the weir at Ponce DeLeon Inlet, Florida, 

because the weir was believed to be causing erosion problems north of the 

inlet and instability in the inlet’s navigation channel. In addition, the weir 

caused safety concerns because boaters were attempting to cross over it to 

go to and from the ocean, instead of using the navigation channel. 

Appendix VI provides a comparison of the proposed Oregon Inlet jetty 

project to similar completed jetty projects.

Corps Applied Lessons 

Learned from Similar 

Jetty Projects in 

Designing the Oregon 

Inlet Jetty Project, but 

Information on Fish 

Larvae Migration Is Not 

Available

Corps officials at the Wilmington District Office stated that in designing the 

Oregon Inlet jetty project, they applied lessons learned from the 

construction and management of similar jetty projects and from internal 

Corps guidance. Specifically, from experiences gained in designing, 

constructing and managing the Masonboro Inlet jetty project in North 

Carolina, Wilmington District officials stated that they learned: 

• how to construct dual jetties to avoid problems with channel migration 

and to ensure that sand accumulates in the intended area,

• how to determine the proper length of the weir section, and

• how to design jetties to prevent the structures from being undermined 

or weakened by erosion.

In addition to the lessons learned from this actual experience, Wilmington 

District officials stated that they used the Corps’ internal guidance on the 

design of jetty projects, which is based on lessons learned from other 

Corps projects. Specifically, this guidance emphasizes the importance of 

having accurate information on sand movement in designing a sand bypass 

system such as the one proposed for the Oregon Inlet jetty project. 

Following this guidance, the district used 20 years of data on sand 

movement in designing the sand bypass system for the Oregon Inlet jetty 

project. 
Page 32 GAO-02-803 Oregon Inlet Jetty Project

Although the Corps used these lessons in designing the Oregon Inlet jetty 

project, there are still some uncertainties about whether the project will 

perform as planned. For example, although the Wilmington District used 

measurements of sand movement taken over the 20-year period, these data 

were obtained from 1956 through 1975 and are now more than 25 years old. 

More recent data on sand movement at Oregon Inlet are available for the 

period from 1976 through 2001; however, the Wilmington District has not 

updated its estimates because it believes that the new data would not 

change its existing estimates significantly. Because this updated data was 

not included in the economic analysis, it is uncertain what effect the more 

recent data would have on the Corps’ estimate of sand movement and 

dredging costs. 

Another issue related to sand movement is the accuracy of the models used 

to make these estimates. Although the Corps used some of the best models 

available to estimate sand movement at Oregon Inlet, Corps officials 

acknowledged that these models are imprecise and generate results that 

could vary by as much as plus or minus 40 percent. This variation could 

affect the actual dredging and sand bypassing costs that would be incurred 

if the jetty project were built. To provide for this uncertainty, the Corps 

included additional dredging costs of about $288,000 annually in its 

economic analysis. 

Another uncertainty relates to the impact of the proposed jetty project on 

the migration of fish larvae. Although none of the similar jetty projects 

with weirs were designed to facilitate fish larvae migration, the Corps 

believes that incorporating a weir into the Oregon Inlet jetty project will 

minimize the impact of the project on fish larvae. However, fisheries 

experts stated that there are no definitive data on how any jetty projects, 

with or without weirs, affect fish larvae migration. 

Commerce and Interior 

Remain Concerned 

That the Oregon Inlet 

Jetty Project Will Harm 

the Environment

Both the Department of Commerce and the Department of the Interior 

support the goal of providing a safe navigation channel through the Oregon 

Inlet for commercial and recreational fishing vessels. However, both 

departments support a dredging-only approach to achieve that goal in an 

environmentally acceptable manner and have raised several concerns 

about the Corps’ plans for stabilizing the inlet with jetties.

Commerce believes that the Corps’ environmental impact statement (EIS) 

for the project is flawed and that the preferred jetty alternative would 

cause unacceptable environmental harm to commercial and recreational 
Page 33 GAO-02-803 Oregon Inlet Jetty Project

fishery resources. Specifically, Commerce’s National Oceanic and 

Atmospheric Administration (NOAA), which is mandated to manage the 

nation’s living marine resources, believes that the Corps’ jetty project 

would eliminate or degrade significant areas of highly productive fishery 

habitat, thereby reducing fishery resources. According to NOAA, such 

habitat is vital for the development of many marine species, including 

shrimp, red drum, summer flounder, and bluefish, which are found in the 

Outer Banks. NOAA maintains that the jetties would alter the near-shore 

currents and reduce successful movement of fish larvae, small juvenile fish, 

and invertebrates, which are dependent on the currents to carry them into 

the sheltered estuaries of the Albemarle and northern Pamlico Sounds. 

According to NOAA, this is a particular concern for the economically 

valuable fish that spawn offshore in the fall and winter, such as flounder. 

While raising these concerns, NOAA recognizes that current data on fish 

larvae migration are not sufficient to quantify the impact that the proposed 

Oregon Inlet jetties would have on fish larvae migration. However, NOAA 

points out that there are no studies or data available on how weirs or jetties 

in general affect fish larvae migration, and it believes that constructing the 

jetties without this information is an unacceptable risk. Commerce also 

noted that without construction of the jetties, the safety record of vessels 

using Oregon Inlet has increased dramatically over the past 20 years. 

Interior, which manages the federally owned land on which the proposed 

jetties would be constructed, has long opposed the project.20 Interior’s 

National Park Service manages the Cape Hatteras National Seashore, 

where the proposed northern jetty would be built, and Interior’s Fish and 

Wildlife Service manages the Pea Island National Wildlife Refuge, where 

the proposed southern jetty would be built.21 Since the Corps first 

prepared an EIS for the project in 1979, both of these agencies have 

consistently raised concerns that the proposed jetties will adversely affect 

fish and wildlife habitat. In general, Interior has expressed the following 

concerns:

• The jetties will increase beach erosion. Interior stated that if the jetties 

are built, erosion and accretion patterns will be modified both north and 

20 In 1992, the Secretary of the Interior issued two conditional permits to the Corps for use of 

Interior lands for jetty construction contingent on completion of project plans and 

environmental studies. These conditional permits were rescinded in 1993.

21 Pea Island National Wildlife Refuge is within the boundary of the Cape Hatteras National 

Seashore.
Page 34 GAO-02-803 Oregon Inlet Jetty Project

south of the inlet, which in turn will increase overwash of the islands, 

especially during storms. This overwash will harm valuable wildlife 

habitat, as well as plants and vegetation that provide food for waterfowl 

and other migratory birds. Interior also stated that this erosion could 

exceed the Corps’ estimates and create a further real threat of additional 

construction on Interior land to save the jetties. Finally, Interior stated 

that the increased erosion would also threaten the infrastructure at and 

adjacent to Oregon Inlet, including state highway 12. Interior noted that 

the design of the Bonner Bridge requires the inlet’s navigation channel 

to remain fixed under a single span of the bridge. However, the 

proposed replacement bridge currently being considered by the state 

has a proposed elevated portion 5,000 feet long that would allow the 

navigation channel to be moved as conditions dictate. According to 

Interior, this would eliminate the need for the jetties and an existing 

rock structure (known as the terminal groin) that was built to protect 

the southern end of the Bonner Bridge. Interior stated that under the 

terms of the permit it granted to the state to construct the terminal 

groin, the structure would probably be removed once the new bridge is 

constructed.

• The sand bypass system that was designed to mitigate the adverse 

effects of beach erosion will permanently alter existing shoreline habitat 

and disrupt shorebird nesting, resting, and feeding areas on a temporary, 

seasonal, or permanent basis. For example, Interior states that each 

sand bypass will harm invertebrate animals (small clams, worms, and 

crabs) that inhabit the shoreline and provide a valuable food source for 

shorebirds and fish. Interior stated that over the years frequent sand 

bypassing of large volumes might permanently eliminate these food 

sources and produce severe long-term adverse impacts on breeding, 

migrating, and over-wintering shorebirds. Among these birds are the 

Great Lakes piping plover population, which is federally listed as 

endangered, and the Atlantic/Canada coast piping plover population, 

which is federally listed as threatened. There is also concern that the 

perpetual placements of incompatible sands will diminish successful 

nesting by the threatened loggerhead sea turtle and green sea turtle. 

Nesting takes place south of the inlet on the refuge, which is an area 

expected to experience the greatest erosion due to the jetties and 

therefore would require the most sand placement. In addition, the 

trapping and bypassing of the sand will not allow the sand to naturally 

migrate into Pamlico Sound, which could have and adverse effect on 

intertidal marshes, sandflats, mudflats, and submerged aquatic 

vegetation, all of which are important fish and wildlife habitat.
Page 35 GAO-02-803 Oregon Inlet Jetty Project

• The weir will not function as planned. Interior stated that the Corps has 

not provided interested agencies with its analysis, studies, or other data 

that would support how the weir will perform and notes that the 

proposed weir design has not been field-tested. Interior also expressed 

concern that the Corps’ planning has not adequately considered the 

impact of the Dare County beach replenishment project on the weir. 

Specifically, according to Interior, the project will take, on average, over 

one million cubic yards of sand from the ocean and place it on the 

beaches north of Oregon Inlet each year. The movement of this 

additional sand from the northern beaches southward toward Oregon 

Inlet would increase the likelihood of the weir becoming landlocked, 

which in turn would allow sand to pass around the north jetty and into 

the ocean bar navigation channel. This would increase the possibility 

that considerable supplemental dredging would be required and/or that 

the Corps may ultimately be required to build longer jetties, as originally 

planned. These actions would significantly increase the cost of the jetty 

project. Interior also said that if the weir were to become landlocked, it 

would nullify the expected benefit of facilitating the migration of fish 

larvae. 

• Construction of the jetties will diminish much of the public’s 

recreational use of the Bodie Island spit, which, according to Interior, is 

contrary to one of the legislative purposes of the Cape Hatteras National 

Seashore. Interior stated that the construction of the north jetty on land 

of the Cape Hatteras National Seashore would block access to a large 

portion of the spit currently used for recreational activities such as 

fishing, and a large section of the spit would be dredged away or used as 

the site of the proposed sand deposition basin.

• The jetty project may not significantly reduce the loss of life at Oregon 

Inlet. Interior points to data which shows that, in some cases, the loss 

of life is not due to conditions at the inlet but rather to such factors as 

alcohol consumption, unfamiliarity with the inlet, navigational errors, 

and the lack of life vests and survival suits. According to Interior, these 

factors would not be corrected by construction of the jetties. Interior 

also raised concerns that the construction of hard structures would 

introduce a new risk to vessels traveling through Oregon Inlet, based on 

accident data from other jettied inlets.

For these and other reasons, NPS does not support the construction of the 

proposed jetty project. NPS stated that the jetty project is not consistent 

with its mission of protecting, and it might actually impair, the resources 
Page 36 GAO-02-803 Oregon Inlet Jetty Project

and values of the Cape Hatteras National Seashore. Further, in May 1982, 

the Fish and Wildlife Service issued a formal determination that the 

proposed jetty project was not compatible with the purposes of the Pea 

Island National Wildlife Refuge, which was established to manage, protect, 

and restore migratory birds and other wildlife.

In addition, in commenting on a draft of the Corps’ August 2001 final EIS, 

the Environmental Protection Agency (EPA) expressed objections to the 

EIS that are similar to the concerns of Commerce and Interior. Specifically, 

in an October 19, 2001, memorandum to the Corps, EPA stated that it 

continues to have objections to the proposed jetty project. These include 

concerns about 

• the potential long-term impacts of the project on a regionally important 

commercial fishery resource, especially disruptions to larval fish 

transport, which EPA believes will be difficult, if not impossible, to 

address;

• the adequacy of the Corps’ proposed mitigation, including whether there 

will be sufficient sand available at critical periods to make the proposed 

sand management plan function as anticipated in preventing projectinduced erosion of Bodie and Pea Islands;

• the need for the project because of uncertainties associated with 

whether the presumed safety benefits will be fully realized; and

• the assumed economic benefits due to professional disagreements 

regarding the assumptions used in the project justification.

EPA believes that the project would result in significant environmental 

impacts that should be avoided in order to ensure adequate protection of 

the environment and that these significant issues must be addressed more 

thoroughly in future deliberations on this project and in the Corps’ Record 

of Decision. 

The Corps asserts that in its final EIS it adequately addressed the concerns 

raised by Commerce and Interior. Specifically, the Corps said that it 

shortened the length of the jetties and incorporated a weir in the north jetty 

and a sand bypassing system to address the concerns raised about fish 

larvae migration and beach erosion. Furthermore, the Corps stated that it 

plans to monitor whether these actions will work and determine whether 

additional adverse impacts result from constructing the jetties. If so, the 
Page 37 GAO-02-803 Oregon Inlet Jetty Project

project will require further mitigation. However, neither Commerce nor 

Interior believes that the Corps’ proposed actions would satisfy their 

concerns.

Because of this impasse, in accordance with regulations under the National 

Environmental Policy Act, on October 16, 2001, Commerce formally 

referred its concerns about the adequacy of the Corps’ EIS to the Council 

on Environmental Quality (CEQ) for its consideration and action. The 

referral process permits federal agencies to bring to CEQ interagency 

disagreements concerning proposed major federal actions that might cause 

unsatisfactory environmental effects. Although Interior did not formally 

refer its concerns to CEQ, it sent a letter to CEQ on November 15, 2001, 

asking the council to consider whether the Corps’ final EIS adequately 

addressed Interior’s environmental concerns.

CEQ may take one or more of several actions, including (1) concluding that 

the process of referral and response successfully resolved the problem; (2) 

initiating discussions with the agencies with the objective of mediation; (3) 

holding public meetings or hearings to obtain additional views and 

information; (4) determining that the issue is not of national importance 

and requesting the lead and referring agencies to pursue their own decision 

processes; (5) determining that the issue should be further negotiated by 

the lead and referring agencies and that the issue is not appropriate for 

CEQ’s consideration until one or more heads of the agencies report to CEQ 

that the agencies’ disagreements are irreconcilable; (6) publishing its 

findings and recommendations, including, where appropriate, a finding that 

the submitted evidence does not support the position of an agency; and (7) 

submitting, where appropriate, the referral and response, together with 

CEQ’s recommendation, to the President for action. CEQ has initiated 

discussions with Commerce, Interior, and the Corps, and it held a public 

hearing on this issue in December 2001. CEQ is in the process of 

completing its assessment and has not established a date for announcing a 

final decision.

The Corps does not plan to issue its Record of Decision on the project until 

CEQ and GAO issue their final reports. However, the Corps stated that 

until these environmental concerns are resolved and Interior indicates it is 

willing to grant the Corps the permits needed to build the project on the 

federally owned land managed by Interior, the Corps does not intend to 

spend additional public resources to further study the economics of the 

jetty project for improving the safety and navigability of Oregon Inlet. 
Page 38 GAO-02-803 Oregon Inlet Jetty Project

In the meantime, the Corps dredged the Oregon Inlet in 2001 in accordance 

with existing NPS and FWS special use permits. In preparation for the 

Corps’ 2002 dredging effort, according to Interior, NPS and FWS assisted 

the Corps in the preparation of an environmental assessment. Based on the 

cooperatively prepared environmental assessment, NPS issued a finding of 

no significant impact and no impairment to park resources and values. 

NPS then issued a special use permit for the 2002 dredging program, which, 

according to Interior, includes a 400-foot wide channel that will require 

dredging away part of the Bodie Island spit. FWS, likewise, issued the 

Corps a special use permit for disposal of dredge material on refuge lands 

during the Corps’ 2002 dredging effort. FWS’s permit allows the Corps to 

deposit about 1 to 2 million cubic yards of dredge spoil on the oceanfront 

beaches of the Pea Island National Wildlife Refuge. According to the NPS 

special use permit, the dredging operation would also eliminate 

approximately 4 acres of wetlands, for which compensatory mitigation will 

be provided by the Corps in the form of enhanced wetlands habitat for 

migratory shorebirds elsewhere on the Bodie Island spit. The Corps’ 2002 

dredging effort is currently underway.

Conclusions The Corps states that it has not been able to maintain Oregon Inlet’s ocean 

bar navigation channel at its authorized depth because of the inlet’s highenergy conditions, especially during storms, and because of funding 

limitations. While it is difficult, if not impossible, to predict the frequency 

and magnitude of storms that impact on the district’s ability to dredge the 

channel, the district has not requested all of the funds it believes are 

needed to adequately perform the dredging. Beginning in fiscal year 2003, 

the district has decided to request the full amount of funds it believes will 

allow it to maintain the channel more reliably.

Although the inlet remains potentially hazardous, we believe that the 

Corps’ economic analysis does not provide a reliable basis for deciding 

whether to proceed with the jetty project. We found significant problems 

with the analysis, including a reliance on outdated and incomplete data, the 

use of unsupported assumptions, and a lack of accounting for risk and 

uncertainty in key variables that could significantly affect the project’s 

benefits and costs. In addition to these economic concerns, the 

Departments of Commerce and the Interior do not believe that the Corps 

has adequately mitigated for environmental concerns, including the 

project’s impact on fish larvae migration, beach erosion, and wildlife 

habitat. Commerce has formally referred its concerns to the Council on 

Environmental Quality for resolution. Interior, which also asked the 
Page 39 GAO-02-803 Oregon Inlet Jetty Project

council to consider its environmental concerns, has been unwilling to grant 

the Corps the permits needed to construct the project on Interior’s lands. 

For this reason, the Corps does not believe it should spend additional 

public resources reassessing the project’s economic analysis until it has 

assurances that this issue will be favorably resolved. We share the Corps’ 

view that it would not be prudent to spend funds reassessing the 

economics of the project until the council resolves the project’s 

environmental concerns and there is some assurance that the Corps will 

receive the permits needed to build the project. 

Recommendations for 

Executive Action

Lacking resolution of environmental concerns from the Council on 

Environmental Quality and construction permits from the Department of 

the Interior, we agree with the Corps that it should not pursue further 

development of the Oregon Inlet jetty project. However, if CEQ favorably 

resolves the environmental issues regarding the proposed jetty project and 

the Corps receives assurance that it can obtain the permits from Interior 

that it needs to build the project, in order to have a reliable basis for 

determining whether the project is economically justified, we recommend 

that the Secretary of the Army direct the Corps of Engineers to

• prepare a new and comprehensive economic analysis of the navigation 

project’s costs and benefits that incorporates updated and complete 

data and corrects all errors in calculations and assumptions;

• obtain the information, where possible, that is needed to address the 

uncertainties—such as the extent to which the jetty project could affect 

the activities of all commercial vessels and the extent to which areas 

outside the ocean bar navigation channel could require dredging—that 

could significantly affect project benefits and costs; and

• submit the revised analysis to the Congress for its use in considering 

future appropriations requests for the project.

Agency Comments and 

Our Evaluation

We provided a copy of our draft report to the Secretaries of the Army, 

Commerce, Transportation, and the Interior, for review and comment. 

Overall, the Army, Commerce, and Interior generally agreed with our 

findings and the recommendations of the report. The Department of 

Transportation did not comment on our overall findings and 

recommendations, but offered specific technical comments. 
Page 40 GAO-02-803 Oregon Inlet Jetty Project

More specifically, the Assistant Secretary of the Army (Civil Works) stated 

that the Department concurs with our finding that the Corps has not been 

able to maintain a safe navigation channel because of the inlet’s highenergy environment and the cost of channel dredging. The Assistant 

Secretary also agrees with GAO’s conclusion and recommendation that a 

new economic analysis of the project is needed to address project 

uncertainties and provide a reliable basis for deciding whether to proceed 

with the project. However, the Assistant Secretary also agreed that it 

would not be prudent to expend additional public funds to conduct an 

economic reanalysis until CEQ resolves the environmental concerns about 

the project and Interior provides assurances that permits needed to 

construct the project will be granted. In addition, the Assistant Secretary 

concurred with the information GAO provided on the performance of eight 

similar jetty projects, their limitations, and the reasons for those 

limitations, and that the information was useful in designing the jetty 

project. Finally, the Assistant Secretary stated that the Corps continues to 

believe that it has made project design changes and taken adequate 

mitigation measures to accommodate Commerce’s and Interior’s concerns 

and that the jetty project is needed to safely accommodate the large 

trawlers that currently operate through the inlet. The Assistant Secretary 

stated that GAO’s discussion of concerns raised by the other agencies 

repeats concerns raised in earlier comments and in the CEQ referral. 

Accordingly, the Assistant Secretary enclosed a copy of the Corps’ 

response to CEQ. This document is not included with the Assistant 

Secretary’s letter in the report but is available on the Web at 

http://www.whitehouse.gov/ceq/referrals.html.

The Department of the Interior generally agreed with our findings, stating 

that the report is an objective and thorough analysis of a complicated 

project with over three decades of development. It also agreed with our 

recommendations, stating that they are consistent with the departmental 

position and comments over the past 10 years. The department also 

provided clarifications on several technical points, which have been 

included in the report as appropriate.

The Department of Commerce noted that the report was thorough, and it 

concurred with our findings and recommendations, specifically that 

considerable revision of the Corps’ economic and other analyses are 

needed before the feasibility and environmental effects of building jetties 

can be determined. The department also offered several specific 

comments, which we incorporated, as appropriate, in the report.
Page 41 GAO-02-803 Oregon Inlet Jetty Project

The Department of Transportation’s U.S. Coast Guard provided oral 

comments on the draft report. Specifically, the Chief, Waterways 

Management Section, District 5, Portsmouth, Virginia, noted that neither 

the GAO report nor the Corps’ economic analysis captured the Coast 

Guard’s costs to maintain the navigation aids at Oregon Inlet with or 

without jetties. The official stated that the service the Coast Guard 

provides is not free, and that costs should be considered in the Corps’ 

economic analysis of the project. The Chief also noted that during the past 

3 years, the primary buoy-servicing vessel the Coast Guard uses at Oregon 

Inlet has increased in length from 157 feet to 175 feet, and its draft has 

increased from 7 to 9 feet. The Chief stated that this buoy tender may be 

the deepest-draft vessel using Oregon Inlet, and the Corps should consider 

the Coast Guard’s operational needs in its design of a navigation channel. 

Otherwise, it will become prudent for the Coast Guard to stop servicing 

aids to navigation in Oregon Inlet. We agree that it would be important for 

the Corps to assess the Coast Guard’s costs of maintaining the inlet’s buoys, 

with or without the jetties, when updating its economic analysis. We also 

agree that it is important for the Corps to do sufficient dredging to allow 

Coast Guard vessels access to the buoys for maintenance.

The full text of the comments provided by the Army, Interior, and 

Commerce are included as appendixes VI, VII, and VIII, respectively, in this 

report.

Scope and 

Methodology

To assess federal efforts to maintain the authorized depth at Oregon Inlet’s 

ocean bar navigation channel, we reviewed documents provided by the 

Corps’ Wilmington District on the frequency and amount of dredging 

accomplished since 1960. We discussed this dredging history with district 

officials to better understand when and why dredging occurred and the 

types of dredges used to maintain the channel. We also reviewed Corps 

documents that discuss the dredging history of Oregon Inlet and show the 

percentage of time that the district has maintained the channel’s authorized 

depth. We also discussed with district officials any circumstances that 

would affect the district’s ability to dredge the channel more frequently and 

thus maintain the authorized depth more consistently. We also reviewed, 

analyzed, and discussed the district’s budget and planning documents for 

fiscal years 1990 through 2001 to ascertain the funding that had been 

requested, approved, and expended for dredging the ocean bar channel at 

Oregon Inlet. We also discussed and obtained information from the Coast 

Guard regarding its maintenance of the navigation buoys at Oregon Inlet to 

learn of any impediments to its efforts.
Page 42 GAO-02-803 Oregon Inlet Jetty Project

To assess the extent to which the Corps’ 2001 economic analysis is useful 

for decision making, we compared the Corps’ economic methods and 

assumptions with standard principles of economic analysis, including 

whether the analysis considered reasonable alternatives, quantified and 

monetized all major categories of benefits and costs, measured benefits 

and costs relative to a baseline, used data based on current economic 

conditions, and accounted for risk and uncertainty associated with key 

assumptions and data. In addition, we compared the Corps’ survey 

methods with standard principles for sampling populations and developing 

and conducting surveys. We focused our review on the Corps’ estimates of 

dredging and jetty costs and on the estimated benefits that had the greatest 

impact on the Corps’ benefit-cost ratio (commercial fishing, recreational 

boating, vessel losses and damages, accidental deaths averted, and land 

preservation). We discussed the benefit-cost analysis with Corps officials 

and, where possible, we collected supporting documentation from which to 

verify the Corps’ analysis. In addition, we reviewed agency and public 

comments about the Corps’ economic analysis. Moreover, we collected 

updated information pertaining to the various categories of benefits and 

costs to ascertain if conditions had changed that would alter the results of 

the Corps’ analysis. For example, to verify Corps and consultant data on 

lives lost, vessels lost, and damage at Oregon Inlet and to develop new data, 

we obtained information from Coast Guard records to determine which 

cases were likely attributable to Oregon Inlet conditions. More details of 

our work on the components of the economic analysis are contained in 

appendix IV.

To obtain information on the performance of similar jetty projects, we 

obtained data from Corps researchers and Corps district offices on jetty 

projects at coastal inlets with design features similar to those planned for 

Oregon Inlet, mainly dual jetties and incorporated weirs. We identified 

eight similar jetty projects—seven built by the Corps and one built by the 

City of Virginia Beach, Virginia, for which the Corps maintains the 

navigation channel. The eight projects are under the jurisdiction of six 

Corps districts: Jacksonville, Florida; Mobile, Alabama; Wilmington, North 

Carolina; Galveston, Texas; Charleston, South Carolina; and Norfolk, 

Virginia. To collect information on how these similar jetty projects have 

performed, we developed a structured interview document that included a 

standard list of questions about each jetty’s physical features, purpose, and 

performance characteristics, such as the operation of the weir and its 

impacts on dredging and beach erosion. We then interviewed staff 

responsible for the projects to obtain answers to the questions. We did not 

verify the answers that district officials provided.
Page 43 GAO-02-803 Oregon Inlet Jetty Project

To determine whether the Corps’ Wilmington District applied lessons 

learned from similar jetty projects in its design of the Oregon Inlet jetty 

project, we interviewed its engineering staff about the information they 

used in developing designs for the proposed Oregon Inlet jetties. 

Wilmington staff said they relied in part on lessons learned from the 

operations of the jetty project at Masonboro Inlet, North Carolina, in 

designing the project for Oregon Inlet. The staff also identified the Corps’ 

internal guidance as helping with the design. We discussed the lessons 

learned with the staff and reviewed Corps planning and engineering 

documents to verify that the lessons had been applied. We also discussed 

with Wilmington District staff, other federal agency officials, and academic 

experts (1) the accuracy of estimates of sand transport used in designing 

the jetty project and (2) the potential for applying lessons learned from one 

jetty project to another.

To identify concerns raised by the Departments of Commerce and the 

Interior about the development of the jetty project, we reviewed comments 

on the Corps’ EIS and design documents and documents developed by 

Commerce and Interior that discussed their concerns. We discussed the 

concerns with officials in these departments to better understand the 

issues. We also met with Wilmington District staff and other project 

proponents, such as North Carolina state government officials and fishing 

industry representatives, and discussed the departments’ concerns with 

them in order to determine the proponents’ views of these concerns and to 

learn of any planned or completed mitigating actions. We also reviewed the 

Department of Commerce’s referral and Department of the Interior’s letter 

and supporting materials sent to the Council on Environmental Quality 

citing their objections to the Corps’ EIS. We also discussed many of the 

environmental issues with various opponents of the project, such as 

environmental groups and some academic experts, in order to better 

understand the issues and their views.

We conducted our work between March 2001 and September 2002 in 

accordance with generally accepted government auditing standards.

As arranged with your offices, unless you publicly announce the contents 

of this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies of this report to the 

Secretaries of Defense, Commerce, and the Interior; the Director, Office of 

Management and Budget; and other interested parties. We also will make 

copies available to others upon request. In addition, the report will be 
Page 44 GAO-02-803 Oregon Inlet Jetty Project

available at no charge on the GAO Web site at http://www.gao.gov. If you or

your staffs have any questions, please call me at (202) 512-3841. Key 

contributors to this report are listed in appendix IX.

(Ms.) Gary L. Jones

Director, Natural Resources

and Environment
Page 45 GAO-02-803 Oregon Inlet Jetty Project

Appendix I

The Corps’ Process for Developing Water Apendxies

Resource Projects ApendxiI

Generally, the Corps becomes involved in a water resource project when 

the local community perceives a need and contacts the Corps for technical 

assistance. If the Corps does not have the statutory authority required to 

study the project, the Congress must provide authorization. Generally, this 

begins with local officials contacting their congressional delegation. After 

receiving authorization, generally through a committee resolution or 

legislation, and an appropriation, a Corps district office conducts a 

preliminary (reconnaissance) study on how the problem could be 

addressed and whether further study is warranted. 

If further study is warranted, the Corps typically seeks agreement from the 

local sponsor to share costs for a feasibility study. The Congress may 

appropriate funds for the feasibility study, including an economic analysis, 

which is conducted by the Corps district office. The feasibility report 

makes recommendations on whether the project is worth pursuing and 

how the water resource problem should be addressed. In conjunction with 

the feasibility study, the Corps must also perform the appropriate 

environmental study under the requirements of the National Environmental 

Policy Act. After public comments on the environmental study are 

considered, the Chief of Engineers transmits the final versions of the 

environmental and feasibility reports to the Congress through the Assistant 

Secretary of the Army for Civil Works and the Office of Management and 

Budget. As long as appropriations are available, the Corps will also prepare 

a preconstruction engineering and design report, which is provided to the 

authorizing committees. The Congress may authorize the construction of 

the project in a Water Resources Development Act or other legislation.

Project construction will occur once the authorized project is included in 

the President’s budget and the Congress appropriates the federal share of 

funds to start the project. Upon appropriation of needed funds, and before 

construction can begin, the Secretary of the Army and nonfederal sponsors 

generally sign a formal project cooperation agreement. The Corps district 

office completes the necessary engineering and design work to develop 

plans and specifications for construction. Private contractors managed by 

the Corps do the construction work.
Page 46 GAO-02-803 Oregon Inlet Jetty Project

Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 2002 ApendxiI

Date Event

05/17/50 P.L. 81-516, The River and Harbor Act of 1950 authorized the Corps to 

dredge the ocean bar navigation channel to a depth of 14 feet.

04/17/63 Committee on Public Works of the U.S. Senate adopts a resolution to 

initiate a study of the Oregon Inlet Jetty Project.

09/26/63 Committee on Public Works of the U.S. House of Representatives adopts a 

resolution to initiate a study of the Oregon Inlet Jetty Project.

04/30/69 Corps submits a favorable report to the Secretary of the Army.

03/18/70 Secretary of the Army submits the Corps’ report to the Congress 

recommending that the ocean bar navigation channel be deepened from 14 

feet to 20 feet, stabilizing Oregon Inlet with jetties, providing a means for 

bypassing sand across the inlet, and creating a 15-acre harbor at Wanchese. 

The benefit-cost ratio is estimated to be 1.4.

12/31/70 The River and Harbor Act of 1970, Public Law 91-611, Section 101, 

authorizes the Oregon Inlet Jetty Project. 

04/15/77 Corps releases drafts of the Phase I General Design Memorandum (GDM)– 

Plan Formulation and Environmental Impact Statement (EIS) for the 

project, supporting the basic plan authorized by the Congress.

06/17/77 Department of the Interior comments on the Phase I GDM and Draft EIS 

state that the principal issues involve jetty construction and impacts on fish 

larvae migration. The comments state that the proposed project would 

result in significant impacts on parklands and that documents do not 

adequately address sand bypassing.

07/29/77 Corps publishes Phase I of the GDM–Plan Formulation.

12/78 Contract is awarded by North Carolina to enlarge the harbor at Wanchese.

05/02/79 Interior meets with the Corps to inform it of the need for special use 

permits for construction on Interior lands. The Corps agrees to prepare a 

supplement to the Final Environment Impact Statement.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 47 GAO-02-803 Oregon Inlet Jetty Project

07/12/79 The Corps sends a letter to the Fish and Wildlife Service (FWS) Regional 

Director outlining right-of-way needs for construction, operation, and 

maintenance of the jetty project and requesting a Cooperative Use 

Agreement for placement of jetties on Pea Island National Wildlife Refuge.

08/03/79 The NPS initiates formation of a Coastal Advisory Committee, which would 

be known as the Inman Panel.22 Later that month the panel issues a report 

outlining the deficiencies in the Corps’ proposal and concluding that the 

project would adversely affect the shoreline environment.

09/21/79 The Corps distributes a draft of a Supplement to the Final EIS to federal 

agencies, which is later designated as Supplement I. The purpose of the 

supplement is to discuss refinement of project features, correct errors in 

the earlier EIS, and address environmental concerns. 

12/03/79 Interior provides comments to the Corps on the draft Supplement to the 

Final EIS, stating that Interior is not “in accord with the current project 

design.” The primary concerns of Interior are that (1) the jetties would 

accelerate already high rates of erosion near the inlet and (2) the jetties 

would alter normal longshore sand transport and likely cause “serious 

erosion problems well beyond the project area.”

08/07/80 The Inman Panel releases a second report entitled Potential Effects of the 

Proposed Oregon Inlet Jetties on Shore Processes Along the Outer Banks 

of North Carolina.

09/80 The Corps publishes the Phase II GDM–Project Design.

09/09/80 Interior informs the Corps that neither the National Park Service nor the 

FWS finds the jetties consistent with the purpose for which land under its 

jurisdiction was established. DOI declines to issue permits for the jetties 

and remains opposed to the project.

12/03/80 The Corps provides Interior with the Phase II GDM. The document 

provides revised details on the design and construction of the dual jetty 

project and a sand bypassing plan.

22 This panel was named for the first chairman, Dr. Douglas Inman, a coastal oceanographer 

with the Scripps Institution of Oceanography.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 48 GAO-02-803 Oregon Inlet Jetty Project

12/28/80 An Interior memo outlines serious environmental concerns regarding the 

construction of the jetties, for example, accelerated beach erosion and 

blockage of larval fish passage, and expresses doubts about the success of 

a Corps sand bypassing program. Interior supports a dredging-only 

alternative.

03/81 North Carolina completes construction of the harbor at Wanchese and a 

seafood industrial park.

07/06/81 Interior Secretary denies permits for the jetty project and states that this 

decision is based on the project’s incompatibility with use of NPS and FWS 

lands. The Secretary directs the FWS and NPS to work with the Corps to 

develop an alternative to the jetties.

11/24/81 The Assistant Secretary of the Army (Civil Works) asks Interior for a 

decision on the Corps’ request for permits to use FWS land and the transfer 

of jurisdiction of land from the NPS.

12/17/81 Interior requests that the Corps examine the feasibility of the dredging-only 

alternative and that the analysis of a dredging-only alternative be 

completed before the Corps pursues the option of jetty construction.

12/22/81 The Assistant Secretary of the Army (Civil Works) authorizes the Corps to 

undertake a comprehensive evaluation of a dredging-only alternative 

recommended by Interior.

05/11/82 The Corps holds a scoping meeting and announces its intention to prepare 

a second supplement to the Final EIS in order to evaluate the dredging-only 

alternative recommended by Interior and to design changes for the jetties.

04/01/83 The Corps releases its report on the DOI dredging-only plan. The report, 

entitled Feasibility Study, Dredging/Near-Shore Disposal Plan, Oregon 

Inlet, North Carolina, concludes that Interior’s dredging-only alternative is 

“functionally infeasible” because it would produce “catastrophic and 

unacceptable” beach erosion. 

04/21/83 Interior Secretary meets with the Assistant Secretary of the Army (Civil 

Works), the North Carolina governor, and the state’s congressional 

delegation. Interior Secretary reiterates that the agency is unable to issue 

special use permits for jetty construction on its land.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 49 GAO-02-803 Oregon Inlet Jetty Project

06/14/83 Bills are introduced in the Congress (H.R. 3288 and S. 1471) to authorize 

the transfer of land from Interior to the Corps for construction of the jetty 

project. Neither bill passes. 

09/83 The Corps publishes Supplement I to the Phase II General Design 

Memorandum addressing jetty spacing, structural design, hydraulic 

stability, subsurface analysis, sand bypassing, and a reanalysis of 

navigation channel dimensions.

02/84 The Corps publishes an economic analysis of the project as directed by the 

Assistant Secretary of the Army (Civil Works) to update an earlier analysis.

08/13/84 The Corps issues a draft of Supplement II to the Final EIS. The document 

states that the dredging-only alternative with near-shore disposal has been 

evaluated and found unacceptable. The preferred alternative is the dual 

jetty project with design modifications.

11/14/84 Interior’s comments on the draft Supplement II to the Final EIS note that 

(1) the dredging-only alternative is not adequately addressed, (2) the 

project would accelerate erosion on Pea Island, and (3) the project may be 

referred to the Council on Environmental Quality.

12/05/84 An Office of Management and Budget (OMB) letter to the Corps states 

concern that project costs will substantially exceed benefits and that 

significant adverse environmental impacts could add to total project costs. 

OMB requests an independent analysis.

05/85 The Corps issues final Supplement II to the Final EIS finding the dredgingonly alternative unacceptable and making the jetties the preferred 

alternative of the Corps. 

08/14/85 Interior comments on the Final Supplement II to the Final EIS stating that, 

overall, Interior is still opposed to the jetties and supports a dredging-only 

alternative.

07/87 The Kearney/Centaur Company releases A Reassessment of the Economic 

Feasibility of the Oregon Inlet Project. This detailed evaluation of project 

economics by a consultant hired by the Corps at OMB’s request concludes 

that project costs would exceed benefits.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 50 GAO-02-803 Oregon Inlet Jetty Project

04/88 The state of North Carolina submits a report responding to the economic 

analysis by Kearney/Centaur. 

06/20/89 FWS issues a right-of-way permit to the North Carolina Department of 

Transportation for constructing a terminal groin23 on the north end of Pea 

Island National Wildlife Refuge to protect the bridge over Oregon Inlet. 

Two days later, the Corps issues permits for construction.

11/89 North Carolina awards a contract for construction of the terminal groin to 

reduce erosion at north end of Pea Island and protect Bonner Bridge using 

the Corps’ design for a 3,125-foot structure with the same dimensions and 

same location as the landward section of the proposed south jetty.

07/90 The Corps releases its third economic analysis of project, entitled 1990 

Update of 1984 Economic Analysis. This report shows lower initial 

construction costs due to the separate construction of the terminal groin.

12/90 The Secretary of the Interior sends a letter to the Secretary of the Army 

providing criteria the Corps needs to meet to obtain Interior’s approval of 

the project. The criteria include (1) approval of the project by the Office of 

Management and Budget; (2) assurance that the project is legal and 

compatible with the park and refuge; and (3) assurance that the project’s 

environmental impacts are assessed and found acceptable.

01/91 A joint Interior and Corps committee is formed to develop an acceptable 

sand management plan.

03/91 Construction of the terminal groin on Pea Island is completed.

12/31/91 The joint Interior–Corps committee releases a report evaluating their 

differences over the scientific and engineering aspects of the jetty project. 

A report by Interior consultants, issued on the same date to the Secretary 

of the Interior, concludes that the jetties would have significant 

unavoidable large-scale impacts on the inlet and the adjacent barrier 

islands and discusses the ecological implications of project, including the 

impact on fish larvae migration.

23 The terminal groin at Oregon Inlet is a rock structure built perpendicular to the shoreline 

to protect the southern end of the Bonner Bridge by preventing the erosion of land on Pea 

Island, into which the bridge is anchored.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 51 GAO-02-803 Oregon Inlet Jetty Project

10/28/92 The Interior Secretary issues two conditional permits to the Corps for use 

of Interior lands for jetty construction, contingent on completion of project 

plans and environmental studies.

01/28/93 U.S. Senator Jesse Helms introduces S. 192, a bill that would require the 

Corps to carry out the construction and operation of the jetty and sand 

transfer system regardless of the final Interior position. The bill also would 

exempt the project from any permit requirements, including those issued 

by Interior.

06/15/93 A new Interior Secretary rescinds the conditional permits that would have 

allowed the Corps to use Interior lands for the construction of the Oregon 

Inlet jetties. The Secretary states that Interior would revisit this decision 

when environmental studies on the project have been completed.

10/94 The Corps initiates coordination with Interior on the design of a sand 

management plan for the Oregon Inlet Project.

01/31/95 U.S. Representative Walter Jones introduces H.R. 758 entitled the “Oregon 

Inlet Protection Act of 1995.” The bill would require the Corps to carry out 

construction and operation of the jetties project. The bill would allow the 

Corps to designate the land required for the project and notify the Interior 

Secretary of the designation.

07/95 The Corps releases a Feature Design Memorandum on the sand 

management plan that recommends a sand bypassing system that will 

emulate natural shoreline processes when the jetties are in place.

07/18/96 The Senate Subcommittee on Parks, Preservation, and Recreation holds a 

hearing on S. 988, a bill directing Interior to transfer administrative 

jurisdiction over certain land to the Secretary of the Army to facilitate 

construction of the jetties and the sand transfer system. Interior opposes 

the bill because of its impact on park and refuge land. The Assistant 

Secretary of the Army (Civil Works) testifies that studies must be 

completed before construction of the project can begin, and that it would 

be premature for the Corps to accept jurisdiction of the land required for 

construction. The bill is not passed.

01/04/99 The Corps releases drafts of Supplement No. 2 to the GDM and Supplement 

III to the project EIS. In the EIS, the Corps’ preferred alternative is 

construction of the dual jetty project and implementation of a sand 
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 52 GAO-02-803 Oregon Inlet Jetty Project

management plan. In the GDM, the Corps proposes a new jetty design that 

shortens each jetty by approximately 1,000 feet, eliminates the sandblocking central barrier within each jetty, and adds a 1,000-foot weir 

section in the north jetty over which sand is expected to move into a 60-

acre deposition basin.

03/04/99 The National Marine Fisheries Service’s (NMFS) comments on the January 

1999 EIS state that “the potential for significant and adverse long-term 

impacts to nationally important living marine resources is such that the 

NMFS has no recourse but to recommend that the jetties not be built.”

03/22/99 Interior’s comments note deficiencies in Supplement III to the EIS and 

reiterate that project goals could and should be met with a dredging-only 

program rather than the dual jetty. The comments state that Interior will 

consider referring the jetty project to the Council on Environmental 

Quality.

05/09/00 U.S. Senator Jesse Helms attaches a rider (the Oregon Inlet, North 

Carolina, Flood Control Improvements) to the fiscal year 2001 Agriculture 

Appropriations Bill that would have transferred the land to build the jetties 

from the jurisdiction of Interior to the Corps.

07/12/01 FWS provides the Corps with a Final Fish and Wildlife Coordination Act 

report for the project. The report recommends that (1) the Corps abandon 

plans for a dual jetty project due to the magnitude of environmental 

consequences and (2) the Corps develop a dredging-only program to 

achieve project goals. 

09/01 The Corps releases final versions of Supplement No. 2 to the GDM and 

Supplement III to the project EIS. The Corps’ preferred alternative remains 

construction of the dual jetty project and implementation of a sand 

management plan.

10/16/01 Commerce refers the project to the Council on Environmental Quality 

(CEQ), stating that the project’s construction would cause unacceptable 

environmental harm to commercial and recreational fishery resources.

12/12/01 CEQ holds a public meeting in Manteo, North Carolina, on the dual jetty 

and weir system project, receives briefings from involved agencies, and 

visits the site of the proposed project.
Appendix II

Chronology of Significant Events for the 

Oregon Inlet Jetty Project, 1950 through 

2002

Page 53 GAO-02-803 Oregon Inlet Jetty Project

04/8/02 The Corps issues an Environmental Assessment for maintenance of the 

channel that includes dredging a 600-foot wider channel on the north side 

of the inlet, removing 26 acres of Bodie Island, and placing the dredged 

material on Pea Island. The assessment and draft Finding of No Significant 

Impact are released for a 30-day public comment period. 

05/02 Interior submits comments on the Environmental Assessment for the 

channel maintenance, recommending that a 400-foot wider channel be 

selected as the preferred alternative in order to minimize ecological 

impacts.

07/02 Interior issues two Special Use Permits—one by NPS and one by FWS—to 

the Corps to construct a wider channel on the north side of the inlet, which 

would remove over 400 feet of the Bodie Island barrier spit within the Cape 

Hatteras National Seashore and deposit the 1 to 2 million cubic yards of 

dredge spoil on the oceanfront beaches of Pea Island. The construction 

would eliminate approximately 4 acres of wetlands, for which 

compensatory mitigation will be provided in the form of enhanced wetland 

habitat for migratory shorebirds elsewhere on the Bodie Island spit.
Page 54 GAO-02-803 Oregon Inlet Jetty Project

Appendix III

Approved Oregon Inlet Dredging Operations 

That Were Not Performed ApendxiI

As shown in table 3, for some of the fiscal years from 1990 through 2001, 

the Wilmington District Office did not perform numerous approved 

dredging operations in the Oregon Inlet ocean bar navigation channel and, 

as a result, did not remove thousands of cubic yards of sand from the 

channel. The District Office did not perform these operations because the 

funds were used on other, higher priorities within the district.

Table 3: Approved Oregon Inlet Dredging Operations That Were Not Performed for Some of the Fiscal Years from 1990 through 

2001 

Note: Costs are expressed in constant 1997 dollars and reflect unspent amounts for dredging the 

ocean bar channel. In addition, there were some years when the Corps spent more funds than were 

made available for dredging but the quantity dredged was 1,889,504 cubic yards less than was 

planned. Totals may not add due to rounding.

a

Actual total exceeds the amount shown because data from some years were not available.

Source: GAO analysis of data provided by the Corps’ Wilmington District Office.

Fiscal 

year Operations not performed

Approved

funding

Cubic yards of sand

planned for removal

1990 Dredge channel with two Corps side-cast dredges $860,000 Not available

Dredge channel with a hopper dredge $845,000 Not available

1994 Dredge channel with two Corps side-cast dredges $1,239,000 Not available

Dredge channel with a hopper dredge $2,809,000 Not available

1996 Dredge channel with two hopper dredges $1,848,000 622,216

1998 Dredge channel with a Corps side-cast dredge $664,000 601,067

Dredge channel with a hopper dredge $929,000 362,279

1999 Dredge channel with a Corps side-cast dredge $506,000 418,958

Dredge channel with a hopper dredge $949,000 164,629

2000 Dredge channel with three Corps side-cast dredges $813,000 663,215

Dredge channel with a hopper dredge $201,000 187,984

Total $11,664,000 3,020,348a
Page 55 GAO-02-803 Oregon Inlet Jetty Project

Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project ApendxiIV

This appendix reviews the Corps’ analysis of the benefits and costs of the 

recommended jetty project for Oregon Inlet. In general, the Corps’ analysis 

has limitations that undermine its usefulness for assessing the economic 

tradeoffs between the current 14-foot dredging program and the Corps’ 

preferred alternative of a jetty system with a 20-foot navigation channel. 

Specifically, the Corps’ analysis (1) failed to consider intermediate channel 

depths between 14 feet and 20 feet, (2) used outdated data to estimate the 

benefits to trawlers and did not account for the effects of the proposed 

jetty project on smaller commercial fishing vessels, (3) used some 

incorrect and outdated data to estimate vessel losses and damages, (4) 

used questionable survey and sampling techniques to estimate recreational 

benefits, (5) did not value land protected from erosion according to federal 

guidelines, and (6) did not fully account for risk and uncertainty in key 

variables used in the analysis. In addition, we also identified other 

limitations, including the fact that the Corps did not account for the 

economic value of the lives that might be saved by the jetty project; in 

addition, its estimate of project cost does not include more recent 

expenditures and is based on an overly optimistic assumption. These latter 

limitations are discussed in the report. 

The Corps Did Not Consider 

Alternative Channel Depths 

between 14 Feet and 20 Feet 

In conducting its economic analysis, the Corps considered three 

alternatives: (1) dredging a 20-foot channel in the spring, (2) dredging a 20-

foot channel in the fall, and (3) constructing dual rock jetties with a sand 

bypassing system, along with a 20-foot channel. The Corps did not analyze 

intermediate channel depths between the current 14 feet and the 

authorized 20 feet. As shown in table 4, the Corps estimated the benefits 

and costs associated with three 20-foot channel alternatives—including the 

proposed jetty project—relative to the current 14-foot dredging program. 

Based on this analysis, the Corps determined that the proposed jetty 

project would provide greater net benefits and a higher benefit-cost ratio 

than either the current program or the other two 20-foot alternatives. 

Corps officials said they considered only alternatives that would achieve 

the 20-foot channel depth because analyses the Corps conducted in 1970 

and again in 1984 demonstrated that the 20-foot channel was needed to 

reliably enable the existing fleet, including 75-foot commercial fishing 

vessels, to pass safely through the ocean bar navigation channel. The 

Corps’ 1970 analysis, which served as the basis for the congressional 

authorization in 1970, found that that a 20-foot channel would be 

economically superior to other channel depths (including 14 feet) because 

it would accommodate existing trawlers and attract some additional 

trawlers and, therefore, result in the plan that has the greatest net benefits.
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 56 GAO-02-803 Oregon Inlet Jetty Project

However, federal guidance for evaluating water resource plans such as the 

proposed Oregon Inlet jetty project states that alternative plans should not 

be limited to those that the Corps could implement under existing 

authorities. Alternative plans should be formulated in a systematic matter 

to ensure that all reasonable alternatives are evaluated.24 In addition, 

according to the state of North Carolina, trawlers used the inlet far less 

frequently than smaller, shallower-draft vessels from 1999 through 2001. 

For example, of the approximately 3,900 average annual commercial 

fishing trips through the inlet from 1999 through 2001, 83 percent were by 

smaller commercial fishing vessels.25 Because these vessels have a 

shallower draft, they may not be as dependent as trawlers upon the deeper 

channel depths.26 Moreover, although the smaller vessels might benefit 

from an increase in the current 14-foot channel depth, the economically 

optimal depth, taking into account all vessels (commercial and 

recreational) currently using Oregon Inlet, may be less than 20 feet. 

Consequently, by not including an analysis of the benefits and costs of 

intermediate channel depths, the Corps’ analysis is less useful for decision 

making because it does not clearly demonstrate that the 20-foot channel 

depth is economically superior to other depths.

24 Economic and Environmental Principles and Guidelines for Water and Related Land 

Resources Implementation Studies, U.S. Water Resources Council, 1983. 

25 Based on the state of North Carolina’s commercial fish landings trip ticket program.

26 According to the state of North Carolina, the smaller vessels averaged about 35 feet in 

length and trawlers averaged about 73 feet. Vessels that are 35 feet in length have a draft of 

approximately 4 to 5 feet.
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 57 GAO-02-803 Oregon Inlet Jetty Project

Table 4: Comparison of Estimated Annual Benefits and Costs of Alternatives for Achieving a 20-Foot-Deep Navigation Channel 

for Oregon Inlet

a Includes categories such as charter boat income and reduced maintenance of navigation aids.

Source: U.S. Army Corps of Engineers 2001 General Design Memorandum.

Corps’ Analysis of Benefits 

to Commercial Fishing 

Vessels Relied on Outdated 

Trip Data and Excluded 

Certain Vessels

In its 2001 General Design Memorandum, the Corps determined that the 

proposed jetty project would generate about $2 million in annualized 

commercial fishing benefits. To derive this estimate, the Corps relied 

primarily on a 1987 consultant’s study of trawler trips taken in the mid1980s. That study determined that 234 trawlers were forced to detour to 

alternative inlets or ports on average about 42 percent of the time, adding 

about 14 hours to the length of their fishing trips. Thus, the study estimated 

that trawlers lost about 27,163 hours detouring to alternative inlets. 

Assuming that the proposed jetty project would save commercial fishing 

vessels these hours, the Corps multiplied the hours by an estimate of the 

hourly cost to operate a commercial fishing vessel ($80.21, including fixed 

and variable operating costs) to estimate the value of the time savings as 

$2,179,000. The Corps divided $2,179,000 by the 17.9 million pounds of fish 

estimated to have been landed through Oregon Inlet by all commercial 

vessels in the mid-1980s to obtain the per-pound savings of 12.2 cents. The 

Alternatives for achieving 20-foot-deep channel

Categories of impacts

Dredging

in fall

Dredging

in spring Jetty project

Increased benefits Reduced operating costs of 

commercial fishing vessels $2,011,000 $2,011,000 $2,011,000

Value of increased recreational boating 

trips $3,367,000 $3,367,000 $3,367,000

Reduced costs associated with 

reduced vessel losses and damages $552,000 $552,000 $552,000

Erosion protection $0 $0 $1,000,000

Value of other categories a $307,000 $307,000 $307,000

Accidental deaths prevented (over 50 

years) 14 14 14

Total increased benefits $6,237,000 $6,237,000 $7,237,000

Increased costs Construction and maintenance $10,601,400 $8,148,400 $4,520,000

Net benefits (increased benefits 

minus increased costs) -$4,364,400 -$1,911,400 $2,717,000

Benefit-cost ratio (increased 

benefits divided by increased 

costs) 0.59 0.77 1.6
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 58 GAO-02-803 Oregon Inlet Jetty Project

Corps then applied the per-pound savings to two different estimates of 

long-term fish harvests: one based on projections developed by the 

National Marine Fisheries Service and one based on projections developed 

by the state of North Carolina. In addition, the Corps conducted an 

uncertainty analysis on each projection to incorporate variability in natural 

fish populations and the effectiveness of management plans. Based on the 

two projections and the uncertainty analysis, the Corps estimated that from 

16,758,000 to 23,313,000 pounds of fish could be available for harvest 

annually over the 50-year life of the jetty project. Multiplying these 

projections by the per-pound savings of about 12.2 cents, the Corps 

estimated that annualized benefits of the proposed jetty project would 

range from $2,011,000 to $2,798,000. 

However, recent data from the state of North Carolina Division of Marine 

Fisheries commercial fishing trip ticket program suggest that trawlers are 

taking fewer trips than they did in the mid-1980s. Moreover, trawlers would 

not likely save the fixed-costs portion of their hourly operating costs even if 

the proposed jetty project were built.27 To illustrate how the Corps’ benefit 

estimate would change using the more recent trawler trip data, we adjusted 

the Corps’ commercial fishing vessel benefits analysis to account for 

trawler trips taken from 1999 through 2001. In addition, we adjusted the 

Corps’ analysis to exclude the fixed costs that would not likely be affected 

by the proposed jetty project. After making these adjustments, we found 

that the Corps estimate of commercial benefits would be reduced by about 

90 percent. Nonetheless, the Corps’ analysis excludes smaller commercial 

fishing vessels; including these vessels could increase this adjusted 

estimate of benefits.

27 Since the Corps assumes no change in the fish harvest, the appropriate measure of savings 

is the marginal cost of the resources, such as fuel and oil, which would be saved by the 

proposed project. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 59 GAO-02-803 Oregon Inlet Jetty Project

For example, according to data obtained from the state of North Carolina, 

vessels 55 feet or longer (defined by the Corps as trawlers) averaged 679 

trips through the inlet from 1999 through 2001.28 Based on these trips and 

the 1987 consultant’s estimate of the fraction (0.42) of trips delayed and the 

average length of the delay (14 hours), trawlers might have been delayed by 

about 4,000 hours annually over this period. Multiplying the hours delayed 

(4,000) by the Corps’ hourly operating cost for a trawler (about $68.00 per 

hour, exclusive of fixed costs) gives an estimated potential annual savings 

of about $272,000. Dividing the annual savings ($272,000) by the average 

number of pounds landed by trawlers through Oregon Inlet from 1999 

through 2001 (8.6 million pounds or 39 percent of the total commercial 

landings) provides potential savings of about 3 cents per pound. We 

applied the fraction (0.39) of trawler catch to the Corps’ two projections of 

future fish harvests to obtain an estimate of the pounds of fish that trawlers 

would be expected to harvest based on current data. For example, based 

on the current harvest data and the long-term projections developed by the 

Corps, trawlers might harvest from about 6,500,000 pounds to 9,100,000 

pounds of fish annually. We multiplied the two estimates of the trawler 

harvest by 3 cents to obtain the estimate of annual operating cost savings. 

We then estimated the present value and annualized over the 50-year period 

using the Corps’ discount rate of 7.125 percent. Thus, adjusting the Corps’ 

analysis in this way generates annualized benefits ranging from about 

$194,000 to $270,000, or about 90 percent less than the Corps estimated.29

The Corps used two other methods to verify the analysis conducted using 

the consultant’s 1987 study. First, the 2001 GDM refers to a 1990 Corps 

economic analysis that found commercial fishing vessels were delayed by 

17,666 hours because of Oregon Inlet conditions, incurring additional costs 

of 11.4 cents per pound to land fish. However, the Corps estimate is not 

28 We used the period 1999 through 2001 because state officials said their vessel licensing 

data from before 1999 are less reliable. Vessel licenses were used to identify the county out 

of which each vessel operated in order to match the counties represented in the consultant’s 

1987 study. Nonetheless, regardless of the vessels’ operating ports, landings data by type of 

fishing gear also suggest trawler trips have declined relative to the consultant’s estimate 

from the mid-1980s. For example, for landings made in Dare, Hyde, Pamlico, and Beaufort 

Counties from 1994 through 1995, vessels using trawl gear landed about 9.3 million pounds 

of fish on 561 trips, while vessels using gill nets landed about 16.3 million pounds of fish on 

about 5,200 trips (including trips via Hatteras Inlet). Vessels using gill nets are generally 

smaller than trawlers.

29 For the adjusted analysis, we assumed no change in the fraction of total trips forced to 

other inlets or ports or in the average length of time a vessel is delayed. Using alternative 

values for these assumptions would change the estimated benefits. 
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 60 GAO-02-803 Oregon Inlet Jetty Project

based on the number of trips or landings made by trawlers in recent years. 

Second, based on a 1995 study by a consultant, the Corps assumed that 56 

full-time vessels were forced to detour eight trips per year. In addition, the 

Corps assumed that other vessels would use Oregon Inlet if the jetty 

project were built. For example, the Corps assumed that 100 additional 

part-time and/or transient vessels would use Oregon Inlet to land fish and 

another 100 vessels would use Oregon Inlet seeking a harbor of refuge 

during storms. However, the Corps could not provide us with the 

documentation to verify the number of full-time vessels, total trips taken, 

trips detoured, number of transient vessels using the inlet, or the number of 

vessels that might seek refuge during storms.

Accounting for the effect of the proposed jetty project on smaller fishing 

vessels could increase this adjusted estimate of the benefits to commercial 

fishing vessels. Nonetheless, because these smaller vessels have a 

shallower draft than trawlers, they may not be as affected by the sand 

accumulations in the ocean bar navigation channel that can be hazardous 

to trawlers. For this reason, the extent to which smaller vessels might 

benefit from the jetty project is uncertain. In addition, to the extent that 

trawlers relocate from other fishing ports (for example, Norfolk) to 

Wanchese, North Carolina, as a result of the jetty project, estimated 

benefits to trawlers could be higher (after netting out transfers between the 

two regions). Moreover, to the extent that trawler captains are detoured or 

delayed more or less often than we assumed, the estimated benefits could 

be higher or lower. Several trawler captains told us that there are fewer 

detours available to them than in the past. According to these captains, the 

Ocracoke Inlet and the Atlantic Intracoastal Waterway from Norfolk, 

Virginia, to Wanchese, North Carolina, are too shallow for trawlers to use 

as a way to avoid passing through Oregon Inlet. These captains said that 

instead of traveling to alternative inlets or ports, they often wait for high 

tide at Oregon Inlet in order to increase the distance between the keel of 

their vessel and the channel bottom. By waiting for high tide, vessels might 

be delayed less time per trip than is assumed in either the Corps’ analysis or 

this adjusted analysis. However, no comprehensive data are available with 

which to verify the average length of time vessels are currently delayed or 

to evaluate the effects of conditions in Oregon Inlet on the operating 

efficiency of the current trawler fleet or smaller commercial fishing 

vessels. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 61 GAO-02-803 Oregon Inlet Jetty Project

Corps’ Estimate of Vessel 

Losses and Damages Is 

Based on Unsupported 

Assumptions and Outdated 

Data 

The Corps estimated that the recommended jetty project would generate 

annualized benefits of $552,000—$160,000 in reduced vessel losses and 

$392,000 in reduced damages to commercial fishing vessels. The Corps 

anticipates that the jetty project would generate these benefits by reducing 

the high waves and sand accumulations in the inlet that contribute to vessel 

losses and accidents. However, the Corps’ estimate has limitations that 

raise questions about its reliability. 

The first limitation is that the Corps’ analysis assumes that all prior 

accidents would be prevented by the jetty project and does not clearly 

control for factors that would be present with or without the jetty project. 

For example, Corps officials told us that under some weather conditions 

the inlet would be hazardous even with the recommended 20-foot channel 

and dual jetties in place. Further, factors the Corps did not control for 

include changes in type of vessel traffic, operator experience, and vessel 

safety technology, all of which will continue to play a role in the number of 

accidents in the inlet, with or without the jetty project. For example, as 

mentioned earlier, the number of trips by trawlers between 1999 and 2001 

is 85 percent less than the number of trips taken in the mid-1980s, and the 

Corps’ analysis does not reflect this change.

Second, the Corps estimate of $160,000 in annualized benefits from 

reduced vessel losses is based on outdated data, some of which are 

incorrect and some of which we could not verify. The GDM states that the 

Corps’ estimates of vessel losses and damages evolved from prior studies 

and the analyses of two consultants’ reports. With regard to vessel losses, a 

consultant’s report completed in 1987 attributed the loss of 21 vessels 

between 1961 and 1986 to conditions in Oregon Inlet.30 The Corps used this 

information to estimate vessel losses in its 1990 economic analysis.31 

Subsequently, a 1995 consultant’s report estimated that the jetty project 

would prevent the loss of 14 vessels during the 50-year life of the project.32 

This report updated data in prior studies, including the 1990 economic 

update by the Corps, and made adjustments because of reductions in the 

number of large fishing vessels using the inlet. However, unlike the 1987 

30 The Kearney/Centaur report, cited earlier.

31 1990 Update of 1984 Economic Analysis: Manteo (Shallowbag) Bay Project, North 

Carolina by the Corps of Engineers’ Wilmington District, July 1990.

32 An Assessment of the Regional Economic Benefits of the Oregon Inlet Stabilization 

Project by the Horizon Planning Group, Wilmington, NC, January 1995.
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 62 GAO-02-803 Oregon Inlet Jetty Project

consultant’s report, the 1995 consultant’s report did not identify specific 

vessels lost or explain its basis for arriving at its estimate of 14 vessels. For 

its 2001 economic analysis, the Corps relied on the 1995 consultant’s report 

that assumed the 20-foot channel and dual jetties would prevent the 

estimated loss of 14 vessels.

We asked the Corps to provide us with the supporting documentation 

behind two previous economic analyses completed in 1987 and 1990. 

Corps officials could not provide this information, stating that the data may 

have been lost or discarded when the office relocated. The 1987 consultant 

report did, however, list the names of the vessels lost between 1961 and 

1986 that it attributed to conditions in Oregon Inlet. Accordingly, we asked 

the Coast Guard for any available accident investigation reports regarding 

these vessels. The Coast Guard had no records for 12 of the 21 vessels that 

the consultant report listed as lost. As shown in table 5, of the nine 

accident investigation reports we reviewed, six of the losses were probably 

attributable to inlet conditions. Of the three losses that we found not 

attributable to the inlet, two occurred at locations other than Oregon Inlet 

and one was caused by mechanical failure. Because we found that three of 

nine vessel losses—33 percent—were not attributable to the inlet, we have 

concerns about the overall accuracy of the data in the report. Since it is 

unclear how information from the Kearney/Centaur report was used in 

updating the estimates of vessel losses for the Horizon Group report and 

the estimates of vessel losses in Corps’ latest economic analysis, we cannot 

determine the exact impact of the errors from the 1987 report on the Corps’ 

estimate.
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 63 GAO-02-803 Oregon Inlet Jetty Project

Table 5: Summary of Information in U.S. Coast Guard Investigation Files on Vessel Losses at Oregon Inlet, 1961 through 1986 

a Not calculated because the accident was not caused by Oregon Inlet conditions.

Source: Case files retrieved by Marine Casualty Investigation Division and printouts of electronic 

marine casualty reports from the Data Administration Division, U.S. Coast Guard.

Date of the 

accident

Vessel name and 

identification 

number

Location of the 

accident

Estimated value of 

lost vessel and 

contents

Was the accident 

caused by Oregon 

Inlet conditions?

Value of the loss in

constant 1997

dollars

10/13/77 M/V Tosco,

505450

The 7th span south of 

the center of Bonner 

Bridge at Oregon Inlet.

$100,000 for the 

vessel

$9,000 for the fish 

catch

Yes

$246,830

11/01/77 F/V Miss Chievious 

Too, 582529

Not specific, assumed 

to occur in Oregon Inlet 

or Pamlico Sound as 

the vessel was entering 

to find safe moorage.

$40,000 for the 

vessel

Yes

$90,580

02/09/79 F/V Dolphin, 258728 The vessel sank in the 

Atlantic Ocean 9 miles 

southeast of Hatteras 

Inlet.

$40,000 for the 

vessel

$2,000 for the fish 

catch

No. The accident did 

not occur in Oregon 

Inlet. a

08/25/79 F/V Ole Ugly, 265219 After departing through 

Ocracoke Inlet, the 

vessel sank in the 

Atlantic Ocean.

$250,000 for the 

vessel

No. The accident did 

not occur in Oregon 

Inlet. a

12/31/81 F/V Coral Breeze, 

543963

At Oregon Inlet’s ocean 

bar.

$170,000 for the 

vessel

$6,500 for the fish 

catch

Yes

$288,493

12/07/81 F/V Lady Phyllis, 

618355

The vessel hit the 

Bonner Bridge.

$4,000 for the vessel No. Inlet conditions 

were calm. Incident 

was caused by 

mechanical failure. a

12/12/82 F/V Lois Joyce, 

605933

In the Oregon Inlet 

channel 150 feet 

outside buoy number 4.

$850,000 for the 

vessel

Yes

$1,307,894

12/04/85 F/V Elizabeth 

Christine, 277218

Within Oregon Inlet 

longitude and latitude 

coordinates.

$150,000 for the 

vessel

Yes

$207,526

06/22/86 F/V Marlina, 249132 Within Oregon Inlet 

longitude and latitude 

coordinates.

$35,000 for the 

vessel

Yes

$47,374

Total $2,188,697
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 64 GAO-02-803 Oregon Inlet Jetty Project

Moreover, based on our review of more current Coast Guard records, from 

1986 through 2001, we identified the loss of four vessels that were likely 

attributable to inlet conditions. These are listed in table 6. Therefore, 

based on our review of the Coast Guard reports that were located on past 

cases and by updating this data using more current records, we identified 

10 vessel losses that occurred because of inlet conditions between 1977 

and 2001. The total value of these 10 vessels is about $2.4 million, or 

roughly $96,000 per year over that 24-year period, which is 40 percent less 

than the Corps’ estimate of $160,000 per year in annualized benefits.33

Table 6: Listing of Vessel Losses and Deaths Attributed to Conditions at Oregon Inlet, June 28, 1986, through November 27, 2001

a

While we reviewed U.S. Coast Guard records from June 28, 1986, through September 30, 2001, we 

included a fatal accident that occurred in November 2001.

Source: U.S. Coast Guard and North Carolina Wildlife Resources Commission.

33 This calculation includes only the vessels listed as lost by the Corps consultant that we 

could verify and vessels identified as lost in our review of more recent Coast Guard records. 

Also, complete records were not available on state registered recreational boat accidents to 

determine how many were lost during the period we reviewed. The 1987 consultant 

apparently did not review such records when identifying vessel losses. 

Date of the 

incident

Vessel name and/or 

identification number Type of vessel

Vessel

length

Number of

deaths

Value of the loss

reported

Value of the loss in

constant 1997

dollars

01/13/89 NC8559AS Fishing 30 0 $30,500 $37,341

12/30/92 High Liner, D620483 Fishing 28 0 $50,320 $55,855

11/20/96 NC9186BK Recreational 17 1 0 0

05/06/00 Little Fly Fisherman, 

D287083

Recreational 

40 0 $130,000 $123,821

11/27/01a

NC9367DA Recreational 16 1 $8,500 $7,934

Total 2 $219,320 $224,951
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 65 GAO-02-803 Oregon Inlet Jetty Project

The third limitation we identified to the Corps’ analysis involves the 

estimated annualized benefits of $392,000 in reduced vessel damages if the 

jetty project is built. Again, the Corps relied partly on data developed in the 

1987 consultant’s study.34 To estimate the value of damages to vessels, the 

consultant interviewed vessel captains and marine repair yards and 

determined that the average annual damage per vessel due to inlet 

conditions was about $7,000. The Corps then multiplied this figure by the 

number of full-time commercial fishing vessels that it estimated were using 

the inlet, which it determined to be 56 full-time vessels, to arrive at 

$392,000 in reduced vessel damages. In its estimate, the Corps assumed 

that all trawlers using the inlet would sustain damages each year. The 

Corps could not provide documentation for this assumption. In contrast, 

as shown in table 7, our analysis of Coast Guard data over this period 

showed that only 10 commercial fishing vessels 55 feet and longer reported 

damages, which totaled on average about $1,700 per year. 

34 1987 Kearney/Centaur study, cited earlier.
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 66 GAO-02-803 Oregon Inlet Jetty Project

Table 7: Listing of Vessel Damages Attributed to Conditions at Oregon Inlet between June 28, 1986, and September 30, 2001

Source: Electronic marine casualty reports from the Data Administration Division, U.S. Coast Guard.

Finally, the Corps’ analysis assessed damages to trawlers only and 

excluded potential damages to other vessels. Our analysis of Coast Guard 

records on reported incidents for all vessels from 1986 through 2001 

showed that conditions in Oregon Inlet caused damages totaling about $7.8 

million, or about $520,000 per year over that 15-year period, which is 25 

percent more than the Corps estimate of $392,000 per year in annualized 

Date of the 

incident

Vessel name and/or 

identification number Type of vessel

Vessel

length

Number of

injuries

Value of the

damage

reported

Value of the damage

in constant 1997

dollars

07/04/86 Northerly Island, D664129 Dredge 194 0 $75,000 $101,516

10/14/86 Capt. Weddell, D654888 Fishing 74 0 0 0

06/12/87 God’s Mercy, D561112 Fishing 77 0 0 0

04/04/88 Schweizer, CG010063 Dredge 133 0 $40,000 $50,832

05/05/88 Kokina, D585863 Fishing 72 0 0 0

05/26/88 Boss Lady, D505741 Fishing 82 0 $15,000 $19,062

04/15/89 Mermentau, D643740 Dredge 197 0 0 0

10/26/90 Northerly Island, D664129 Dredge 194 0 $6,500,000 $7,658,772

09/07/92 Uncloudy Day, D950979 Fishing 55 0 $3,000 $3,330

01/13/94 Louise, MS4131AP Fishing NA 0 0 0

04/27/94 Lucky Thirteen, D606275 Fishing 65 0 0 0

07/22/94 Gallant Fox, D567254 Fishing 72 0 $1,000 $1,062

04/07/95 Portugal, D608405 Fishing 74 0 0 0

10/08/95 Hoosier State, D581970 Tug 43 0 0 0

12/07/95 Clayton Reed, D683286 Fishing 45 0 $6,000 $6,236

12/11/95 Atchafalaya, D630005 Dredge 197 0 0 0

06/03/97 Hooker, D592896 Passenger 46 1 0 0

11/02/99 War Cry, D614462 Recreational 76 0 0 0

12/31/99 Capt. Malc, D607993 Fishing 81 0 $300 $292

02/22/00 Adrien Rose, D538410 Fishing 46 0 0 0

02/20/01 Snoopy II, D563195 Fishing 52 0 $500 $467

05/30/01 C-Venture, D539167 Fishing 73 0 $1,500 $1,400

Total

Average loss per year (15 years)

$6,642,300

$301,923

$7,842,969

$356,499

Total for 10 fishing vessels 55’ and over

Average loss per year (15 years)

$20,800

$1,387

$25,146

$1,676
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 67 GAO-02-803 Oregon Inlet Jetty Project

benefits.35 However, most of the total damages—$7.7 million—were 

attributable to one accident involving a dredge, which, torn from its anchor 

by a storm, struck and caused the collapse of a part of the bridge that spans 

Oregon Inlet. If the dredge accident were removed from the calculation, 

the average damages over the 15-year period would be about $12,000 per 

year, or nearly 98 percent less than the Corps’ estimate. 

Although we could verify some of the earlier estimates of vessel losses and 

damages and were able to provide more current data from a review of 

accident reports, the extent to which past deaths and vessel losses and 

damages might have been prevented by the Corps’ proposed jetty project is 

not known. Consequently, we did not revise the Corps’ estimate of benefits 

to include this more recent data.

Corps Did Not Clearly 

Explain How It Derived Its 

Estimate Of Lives That 

Might Be Saved by the 

Proposed Jetty Project 

In addition to not incorporating the economic value of the lives that might 

be saved by the proposed jetty project in its estimate of benefits, the Corps 

did not clearly explain how it estimated that 14 lives might be saved over 

the 50-year life of the project. Corps’ Wilmington District Office officials 

told us that they used their own studies and the 1987 Kearney/Centaur 

report as the basis for estimating that 14 lives might be saved by the 

project. The Kearney/Centaur report identified that 20 lives were lost with 

an associated loss of 21 vessels in Oregon Inlet from 1961 through 1986. We 

attempted to get data from the Corps that would document the 20 lost lives, 

but the Corps had not retained the supporting documentation for the 

Kearney/Centaur report. As a result, we asked the Coast Guard to provide 

any accident reports that it had relative to the vessel losses and 20 lost lives 

identified in the Kearney/Centaur report. The Coast Guard could only 

provide information on nine of the lost vessels. Based on our review of the 

nine cases, we found that the Kearney/Centaur report excluded four deaths 

resulting from a 1977 vessel loss even though information in the Coast 

Guard accident report implicated inlet conditions in the loss. In addition, 

we found that one death included in the Kearney/Centaur report did not 

occur in Oregon Inlet. Moreover, based on our review of more current 

Coast Guard records from 1986 through 2001 (see table 6 above), we 

identified two deaths—one in 1996 and the other in 2001—that were 

attributable to inlet conditions. Both of these accidents involved small 

recreational boats. Consequently, based on our review, we found that at 

35 Our estimate of damages is based on reported incidents and does not include any damages 

that were not reported to the Coast Guard. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 68 GAO-02-803 Oregon Inlet Jetty Project

least six deaths were attributable to conditions in Oregon Inlet over the 

25-year period from 1977 through 2001, which is slightly less than the Corps 

estimate over a comparable period. However, whether these accidental 

deaths would have been prevented by the jetty project is uncertain. As 

mentioned above, the Corps’ analysis assumed that all prior vessel 

accidents that included deaths would be prevented by the jetty project 

without clearly controlling for factors that would be present with or 

without the jetty project. For example, Corps officials told us that under 

some weather conditions the inlet would be hazardous even with the 

recommended 20-foot channel and dual jetties in place. 

Corps Relied on Outdated 

Data Collected with 

Questionable Survey and 

Sampling Techniques to 

Estimate Recreational 

Benefits

The Corps estimated that the jetty project alternative would generate about 

$3.4 million dollars in annualized benefits for recreational boaters by 

reducing high waves and sand accumulation in the ocean bar navigation 

channel, thus allowing for more trips. This estimate includes an estimated 

$2.8 million in benefits for private recreational boats, with the remaining 

benefits for anglers on charter and party boats. We could not verify the 

Corps’ estimates because it did not retain supporting documentation, and 

independently calculating the estimates would require an inordinate 

amount of time and resources. However, based on our review of the Corps’ 

approach and methodology used in developing the estimates, we have 

identified three limitations that raise questions about the reliability and 

usefulness of the estimated benefits. 

First, the Corps’ original data collection effort, conducted in 1983, used a 

survey instrument that may have biased the boaters’ responses in favor of 

the jetty project. For example, to estimate the additional trips that private 

recreational boaters might be willing to take if the jetty project were 

constructed, the Corps mailed a survey to 3,876 registered owners of 

recreational power and sail boats at least 19 feet long who were likely to 

have used Oregon Inlet in 1983. The Corps received 1,044 usable 

responses36 and from them concluded that private recreational boaters 

would increase their average annual use of the inlet from 8.59 trips through 

the Inlet per year to 19.34 trips per year if the jetties were built. The cover 

36 In 1983, the Corps reported using 1,094 responses and a response rate of 46 percent. In 

2001, the Corps reported using 1,044 responses, stating that 176 surveys were undeliverable 

and 681 others were considered “not usable.” The Corps deemed a response “not usable” if 

the respondent no longer owned a boat, the boat was not used in the ocean, or because the 

information provided was “invalid” or appeared duplicative. The 2001 General Design 

Memorandum does not project the survey results to the entire population of respondents. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 69 GAO-02-803 Oregon Inlet Jetty Project

letter accompanying the mail survey included the following introduction to 

the topic, stating that “despite 22 years of intensive maintenance dredging, 

the Corps has been able to maintain the channel depth only 25 percent of 

the time and has never been able to maintain the 400-foot channel width” 

and that “numerous groundings, vessel losses, personal injuries, and deaths 

have occurred.” In addition, the survey instrument asked respondents to 

estimate the number of days per year they “currently use” Oregon Inlet and 

the number of days per year they “would use Oregon Inlet if it were 

stabilized with dual jetties and a deeper, more reliable channel.” The 

wording implied that the channel would be safely passable all of the time if 

the jetty project were built, which is not the case. Corps officials 

acknowledge that even with the jetty project there will be periods when 

weather conditions will make the inlet impassable.

Concerning the estimated use of the inlet, a 1987 consultant’s report noted 

that some survey responses seemed too extreme to be credible. For 

example, on average, respondents indicated they currently used the inlet 11 

days each year. However, a number of respondents indicated a 

substantially higher use, with the highest reported estimate being 250 days 

per year. To address this concern in its most recent economic analysis, the 

Corps calculated new estimates using only responses that indicated a use 

of 60 days or less. This resulted in the Corps excluding 23 responses that 

were above this number. However, the 60-day threshold was arbitrary, and 

it neither accounts for the possibility that some responses above the 

threshold may be legitimate nor addresses the problem that responses 

below the threshold may have also been subject to biased wording. While 

the overall estimated benefits are lower than they would be if all responses 

were included, we could not determine the reasonableness of these 

estimates. The Corps does not believe the surveys contained bias. They 

said that the Office of Management and Budget (OMB) approved the 

surveys and that the wording “deeper, more reliable channel” would be an 

accurate description of the channel with the implementation of the jetty 

project. Both the Paperwork Reduction Act and OMB’s process for 

reviewing surveys have changed since 1983. However, the OMB official 

who currently reviews Corps surveys told us that the current OMB 

approval process does not ensure that a survey instrument is free from 

bias, although the reviewer may suggest changes if he or she detects bias, 

along with any other editorial comments. Because OMB does not keep 

records beyond 10 years, we could not determine the nature and extent of 

OMB’s comments concerning the Corps’ 1983 surveys. 
Appendix IV

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Proposed Oregon Inlet Jetty Project

Page 70 GAO-02-803 Oregon Inlet Jetty Project

Second, the Corps’ 2001 economic analysis of recreational benefits relied 

on survey data from 1983 and 1984. These data are outdated and may not 

reflect the economic value that today’s boaters would place on any 

additional trips they would be able to take if the jetty project were built. 

The demand for recreational fishing is dependent upon factors such as the 

current cost (for example, expenses and time incurred in traveling to the 

site) and the current availability of substitute fishing sites and other 

recreational opportunities.37 For its most recent analysis, the Corps 

updated the original survey data by increasing the results by the rate of 

growth in regional tourism and visitation from 1984 through 1995. The 

Corps then used the updated survey data as a starting point for projecting 

recreational demand another 50 years into the future—the life of the jetty 

project—to 2051. However, changes in tourism and visitation primarily 

reflect changes in population rather than changes in relative prices or 

substitute recreational opportunities. Consequently, the reliability of the 

Corps’ recreational demand projections is questionable. Corps officials 

acknowledged that their recreational benefit estimates are based on 

outdated data but said they had not received funding to update the data. In 

addition, they believe that recreational activity has increased at Oregon 

Inlet and that using data that are more current would not change estimated 

recreational benefits of the jetty project. Nonetheless, the Corps does not 

have current data on the economic value that recreational boaters would 

attribute to the jetty project alternative to support its contention.

Third, in estimating the economic value of the additional fishing trips, the 

Corps used data collected from anglers on private boats and charter boats 

during three 1-week periods in August, September, and October of 1983. 

The Corps used these data to estimate that the average value of a fishing 

trip was $22.56 per person per day. However, both the number of fishing 

trips and the type of catch vary considerably over the year. The 3-month 

period during which the data were collected is the highest-use period for 

recreational fishing. The value of a fishing trip, according to those fishing 

in August, September, and October, may differ from the value assigned by 

those fishing during other months because the number of boats and anglers 

varies by season, as does the type of fish caught and the severity of weather 

and sand accumulation in the inlet. Therefore, since data were gathered 

37 The Corps used a “travel cost” model to estimate the value of the additional trips. This is a 

technique for approximating the value that recreationists would be willing to pay for the use 

of a site, based on factors such as the expenses and value of the time required to travel to 

the site. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 71 GAO-02-803 Oregon Inlet Jetty Project

only from anglers during the peak recreational season, the Corps’ estimate 

of the value of a fishing trip may not be a reasonable representation of the 

value of such a trip for the entire fishing season. Furthermore, there was 

no update of these data in the Corps’ most recent economic analysis. 

Corps officials said that since most fishing trips occur during the months of 

August, September, and October, values for those months would be 

weighted most heavily, even if data from additional months were collected, 

and that there was no reason to believe that trips in other months would be 

less valuable. For example, they said charter boat fishing rates are the 

same in other months as they are in the highest-use months. Nonetheless, 

the Corps did not incorporate the value of the additional trips that 

recreational anglers fishing in lower-use months might be willing to take if 

the proposed jetty project were built. The value of the additional trips 

during lower-use months could be lower or higher than the value in higheruse months for several reasons, including the type of fish that are available, 

the weather, and the particular preferences of the angler. 

Corps’ Approach to Valuing 

Benefits Associated with 

Reduced Erosion Is 

Inconsistent with Federal 

Guidelines 

The Corps estimated that the proposed jetty project would yield about 

$1 million in annualized benefits by preventing the erosion of beaches to 

the north and south of Oregon Inlet. Because the protected land to the 

north of the inlet is part of the national seashore and to the south of the 

inlet is part of a national wildlife refuge, the benefits derived from the jetty 

project would be the recreational opportunities generated from the public 

use of the protected land. However, the Corps used valuation techniques 

that are not consistent with federal guidelines for valuing recreational 

benefits. As a result, the reliability of the Corps’ estimate of $1 million for 

erosion prevention is questionable and thus less useful because it does not 

reflect the value of the land as it is currently used for recreation and as 

wildlife habitat. 

Federal guidance states that benefits arising from a project that generates 

recreational opportunities should be measured in terms of the willingness 

of users to pay for the recreational opportunity. For example, the fees 

users are willing to pay to visit a site and any unpaid value38 enjoyed by the 

recreationist can be used to measure benefits. Although the Corps’ 

38 This unpaid value is called “consumers’ surplus” and is a standard measure of the net 

benefit derived from purchasing a good or service. Since the protected land is publicly 

provided and no fees are charged to enter the site, the value of the land can be estimated 

using indirect means such as the travel cost model. 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 72 GAO-02-803 Oregon Inlet Jetty Project

economic analysis states that the protected land could be valued in terms 

of its use for recreation, the Corps chose not to do so because an earlier 

consultant’s report39 found drawbacks with an approach that based the 

value of the land on the willingness to pay for recreational opportunities. 

In particular, the consultant’s report states that the land has a “uniqueness 

value” to the nation that would not be captured by techniques based on 

recreational visitation. As a result, the Corps did not use willingness to pay 

for recreational opportunities to calculate the value of the land. However, 

although the Corps agreed with the consultant’s argument, neither of the 

two valuation methods used by the Corps measured the uniqueness value 

of the land.40 

The Corps used two different methods to derive two separate estimates of 

the benefits associated with the land that would be “protected” by the jetty 

project. Under one method, the Corps assumed that the jetty project would 

protect 5 acres of land per year from natural erosion. To determine the 

benefits, the Corps used the per-acre cost of bypassing sand (about 

$200,000) instead of the land’s value for recreational use. This method is 

inconsistent with federal guidelines, because the cost of preventing the 

erosion does not reflect willingness to pay for recreational use of the land. 

As a result, we could not determine whether the Corps’ estimate overstates 

or understates the value of the land for recreational use. 

Under the second method, the Corps assumed that the jetty project would 

prevent erosion of 9.5 acres from nearby beaches each year, or roughly 

twice as much land as would be protected under the first method. District 

officials said they used the market value of local, private, undeveloped, 

non-erodible, oceanfront property as a way to reflect the land’s opportunity 

cost—the value of the land in its alternative best use—to initially value the 

protected land at about $426,000 per acre. However, because the protected 

land is erodible, the Corps reduced that value by 75 percent to make the 

land worth about $107,000 per acre. Under this method, the total value of 

the protected land was estimated to be roughly $1 million. However, Corps 

officials did not have documentation supporting the basis for reducing the 

value of the protected land by 75 percent. Moreover, since the land being 

protected is public land, it is not likely that the land will be sold for private 

39 The Kearney/Centaur report, cited earlier.

40 Economic techniques that measure total economic value could assess whether the acres 

saved would add to the uniqueness value of the national seashore and the wildlife refuge 

(use and non-use values). 
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 73 GAO-02-803 Oregon Inlet Jetty Project

use. Further, this approach does not consider the land’s use for recreation 

and is, therefore, inconsistent with federal guidelines for estimating 

recreational benefits. As a result, it fails to provide decision makers with 

reliable information regarding these potential benefits.

Corps officials said that their guidelines for conducting economic analysis 

allow the benefits of environmental protection projects to be judged equal 

to their costs, which is why the Corps used the cost of bypassing sand as 

the value of the land. Nonetheless, as mentioned above, the cost the Corps 

derived is not based on a measure of the willingness to pay, and, as a result, 

the extent to which the Corps’ estimated benefits approximate the value of 

the land for recreation purposes is not known.

The Corps Did Not Account 

for Risk and Uncertainty 

Associated with All Key 

Variables 

In developing its estimate of the benefits and costs of the jetty project 

alternative, the Corps did not fully account for the extent to which the net 

benefit estimates would be affected by the risk and uncertainty associated 

with potential measurement errors and variability in the underlying data 

and assumptions.41 

The economic analysis did account for some risk and uncertainty for some 

variables. For example, in developing its estimate of the operating costs 

that trawlers would save in harvesting fish if the jetty project were built, 

the Corps adjusted its estimates to reflect the year-to-year variability in fish 

populations. In addition, in developing its estimate of the cost to construct 

the jetty project and operate the sand bypassing system, the Corps 

increased its estimate by about 15 percent to account for unforeseen events 

that might increase construction costs. The Corps also included additional 

costs for sand bypassing to ensure that neighboring beaches do not erode 

at a greater rate than anticipated. 

However, the Corps did not assess the effect of risk and uncertainty for 

other key data and assumptions on the net benefit estimates. For example, 

the Corps used single or “point” estimates for the amount of sand estimated 

to pass over the weir; the trips and operating cost savings for commercial 

41 Federal guidance for water resources planning states that the effect of the risk and 

uncertainty should be examined. Risk reflects situations where potential outcomes can be 

described using reasonably well-known probability distributions. Uncertainty reflects 

situations where potential outcomes cannot be described in objectively known probability 

distributions.
Appendix IV

Review of Corps’ Economic Analysis of the 

Proposed Oregon Inlet Jetty Project

Page 74 GAO-02-803 Oregon Inlet Jetty Project

fishing vessels; the additional trips that recreational boaters might take; the 

extent to which the jetty project might prevent vessel losses, damages, and 

accidental deaths; and the amount of dredging that might be required in the 

interior channels even with the proposed jetty project in place. For 

example, the amount of sand that is expected to pass over the weir and be 

used to reduce erosion on neighboring beaches is subject to some 

uncertainty because of errors inherent in modeling sand transport as well 

as variability in the frequency of storms and in ocean currents. By not fully 

assessing the effect of uncertainty, a decision maker might not be aware of 

the extent to which the net benefit estimates might change if the underlying 

assumptions deviate from the values assumed by the Corps.
Page 75 GAO-02-803 Oregon Inlet Jetty Project

Appendix V

Comparison of the Proposed Oregon Inlet 

Jetty Project to Similar Completed Jetty 

Projects ApendxiV

Table 8 compares key characteristics of the proposed Oregon Inlet jetty 

project to other similar jetty projects located on coastal inlets of the 

Atlantic Ocean and Gulf Coast of the United States. 

Table 8: Key Characteristics of the Proposed Oregon Inlet Jetty Project and Similar Completed Jetty Projects

a

 Tidal prism is the volume of water flowing in or out of an estuary between high and low tides.

Source: GAO interviews with officials responsible for the projects.

Key 

Characteristics:

Proposed 

for 

Oregon 

Inlet, NC

Murrells 

Inlet, SC

Colorado 

River, TX

Ponce 

DeLeon, 

FL

St. Lucie, 

FL

Perdido 

Pass, AL

East 

Pass, FL

Rudee, 

VA

Masonboro, 

NC

Number of jetties 222222222

Location of first 

jetty

North side 

of inlet

North side 

of inlet

East side 

of inlet

North side 

of inlet

North side 

of inlet

East side 

of inlet

East side 

of inlet

North side 

of inlet

North side of 

inlet

 Year completed Proposed 1979 1990 1971 1982 1969 1969 1968 1966

 Length in feet 10,020 3,455 3,500 4,200 3,975 1,800 1,220 765 3,650

Location of second 

jetty

South side 

of inlet

South side 

of inlet

West side 

of inlet

South side 

of inlet

South side 

of inlet

West side 

of inlet

West side 

of inlet

South side 

of inlet

South side of 

inlet

 Year completed Proposed 1980 1990 1969 1982 1969 1969 1968 1980

 Length in feet 6,575 3,319 2,900 2,700 1,000 1,800 3,400 815 3,450

Typical tidal prisma

(in millions of 

cubic feet)

2,810.0 580.0 1.7 509.0 5.2 435.6 1,620.0 16.6 680.0

Sediment transport, in cubic yards, as viewed from land

 Left 611,000 54,000 0 348,000 72,600 130,000 65,000 378,000 200,000

 Right 1,473,000 186,000 600,000 363,000 130,000 65,000 130,000 93,000 500,000

 Net 862,000 132,000 600,000 15,000 57,400 65,000 65,000 285,000 300,000

Weir location North jetty North jetty East jetty North jetty North jetty East jetty West jetty South jetty North jetty

Weir length in feet 1,000 1,880 1,000 Formerly 

1,800

900 1,000 Formerly 

1,000

475 1,000

Weir elevation in 

feet above mean 

low water

1.5 2.2 0.74 Closed 0 -0.5 Closed 2.15 2.16

 Left 611,000 54,000 0 348,000 72,600 130,000 65,000 378,000 200,000

 Right 1,473,000 186,000 600,000 363,000 130,000 65,000 130,000 93,000 500,000

After jetties, 

percentage of time 

channel less than 

authorized depth

N/A 1 70 10 or less 80 0 20 7 to 8 Less than 5 
Page 76 GAO-02-803 Oregon Inlet Jetty Project

Appendix VI

Comments from the Department of the Army ApendxiVI
Appendix VI

Comments from the Department of the Army

Page 77 GAO-02-803 Oregon Inlet Jetty Project
Page 78 GAO-02-803 Oregon Inlet Jetty Project

Appendix VII

Comments from the Department of the 

Interior ApendxiVI
Appendix VII

Comments from the Department of the 

Interior

Page 79 GAO-02-803 Oregon Inlet Jetty Project
Appendix VII

Comments from the Department of the 

Interior

Page 80 GAO-02-803 Oregon Inlet Jetty Project
Appendix VII

Comments from the Department of the 

Interior

Page 81 GAO-02-803 Oregon Inlet Jetty Project
Page 82 GAO-02-803 Oregon Inlet Jetty Project

Appendix VIII

Comments from the Department of 

Commerce ApendxiVI
Appendix VIII

Comments from the Department of 

Commerce

Page 83 GAO-02-803 Oregon Inlet Jetty Project
Appendix VIII

Comments from the Department of 

Commerce

Page 84 GAO-02-803 Oregon Inlet Jetty Project
Appendix VIII

Comments from the Department of 

Commerce

Page 85 GAO-02-803 Oregon Inlet Jetty Project
Appendix VIII

Comments from the Department of 

Commerce

Page 86 GAO-02-803 Oregon Inlet Jetty Project
Page 87 GAO-02-803 Oregon Inlet Jetty Project

Appendix IX

GAO Contact and Staff Acknowledgments ApendxiIX

GAO Contact (Ms.) Gary L. Jones (202) 512-3841

Staff 

Acknowledgments

In addition, Tim Guinane, Roy Judy, Ken McDowell, Cynthia Norris, Anne 

Rhodes-Kline, John Scott, Amy Webbink, and Jim Yeager made key 

contributions to this report.

(360049)
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